Insulating material containing cycloolefin polymer

ABSTRACT

An insulating material comprising a cycloolefin polymer, specifically, an interlayer insulating material for a high-density assembly board having interlayer-connecting via holes at most 200 μm in diameter, comprising a cycloolefin polymer containing at least 50 mol % of a repeating unit derived from a cycloolefin monomer; a dry film formed from a curable resin composition comprising a polymer having a number average molecular weight within a range of 1,000 to 1,000,000 as measured by gel permeation chromatography, and a hardener; and a resin-attached metal foil obtained by forming a film of a cycloolefin polymer on one side of a metal foil. Laminates, multi-layer laminates and build-up multi-layer laminates making use of these materials, and production processes thereof.

TECHNICAL FIELD

[0001] The present invention relates to insulating materials containinga cycloolefin polymer and their uses. More particularly, the presentinvention relates to high-density assembly boards which are excellent inthe ability to form minute interlayer-connecting via holes and alsoexcellent in heat resistance, interlayer insulating materials suitablefor use in the production of such a high-density assembly board, andpackages of semiconductor parts produced by using the high-densityassembly board. The present invention also relates to dry filmsexcellent in processability, adhesion property and productivity,laminates making use of such a dry film and production processesthereof. The present invention further relates to resin-attached metalfoils with a film of a cycloolefin polymer formed on one side of a metalfoil, laminates obtained by laminating such a resin-attached metal foil,and a production process of a build-up multi-layer laminate using such alaminate, and more particularly to resin-attached metal foils andlaminates, which are excellent in chemical resistance, adhesion propertyand reliability, and a production process thereof.

BACKGROUND ART

[0002] With the rapid advancement of advanced information-orientedsociety in recent years, there is a strong demand for the enhancement ofthroughput capacity of information processing apparatus, i.e., thespeeding up. In addition, their miniaturization and weight saving arerequired so as to be portable.

[0003] Of these requirements, in order to achieve the speeding up of theinformation processing, it is effective to make the interconnectedwiring of passive parts and active parts such as LSI, memory and so asshort as possible so as to make wiring density high. This technique isalso effective for the miniaturization and weight saving.

[0004] Printed wiring boards by which the width and pitch (line andspace; L/S) of wiring are make small to make the high-density assemblyof electronic parts such as LSI chips possible have heretofore beenknown as high-density assembly boards. In this case, in order to makethe great reduction of the wiring pitch (L/S) possible, it is necessaryto form minute interlayer-connecting via holes having a diameter of atmost 200 μm, which is far smaller than those used in productiontechniques for general printed wiring boards.

[0005] It is difficult to form the interlayer-connecting via holes atmost 200 μm in diameter by the drilling used in the formation of viaholes in the conventional printed boards. It is hence necessary to usephotolithography in which photosensitivity is imparted to an insulatingmaterial to conduct ultraviolet exposure, or etching by a laser.Therefore, as properties required of the insulating material, it isimportant to permit easily imparting photosensitivity and heighteningthe aspect ratio (thickness of an insulating film/connection viadiameter) of via holes by the photolithography or etching by a laser toeasily form minute via holes.

[0006] An insulating material used in an interlayer insulating film of ahigh-density board is particularly required to have high heat resistancethat can withstand heat generated by high-density assembly andhigh-density mounting processes of electronic parts, and low waterabsorption property for ensuring insulation reliability in a narrowwiring pitch and a thin insulating layer. In addition, since speeding upand the use of high frequency are required in the field in which thesehigh-density assembly boards are used, it is desirable for theinsulating material to have excellent dielectric properties such as lowdielectric constant and low dielectric loss tangent.

[0007] As the insulating material for the interlayer insulating film, ithas heretofore been disclosed in, for example, “Method for FormingMinute Pattern of Photosensitive polyimide and Application thereof toMCM Use; Collection of Lecture Papers in Seventh Science Lecture Meetingof Society of Printed Circuit Board, pp. 39-40” to use polyimide towhich photosensitivity has been imparted. However, the photosensitivepolyimide is excellent in heat resistance and dielectric properties, butthe bottom of its film is hard to cure upon ultraviolet exposure, and soit has involved a problem that the wall surface of a via hole formedtherein is easy to swell by development. Even when non-photosensitivepolyimide is processed by a laser, there has been a problem that theformation of a minute via hole is difficult by reason of too highabsorption of laser or difficulty of being decomposed. In addition,since the polyimide resin has a high water absorptivity, its dielectricproperties are greatly deteriorated, and insulation reliability islowered by moisture absorption in high-temperature and high-humidityconditions in particular. Further, the polyimide resin undergoesbubbling of water in the resin under high-temperature conditions insolder mount or the like. Such bubbling has formed the cause of blisterand cracking and hence become a great problem.

[0008] For example, Japanese Patent Application Laid-Open Nos.170070/1995, 41167/1996 and 148837/1996 disclose a technique in which amaterial obtained by imparting photosensitivity to such a bisphenol Atype epoxy resin as used in general printed wiring boards is used.However, this photosensitive epoxy resin has been subjected to acrylmodification for the purpose of imparting the photosensitivity and hencehas involved a problem that the dielectric properties of the resultingboard are greatly deteriorated. In addition, the photosensitive epoxyresin has also involved the same problem as in the photosensitivepolyimide as to the formation of the via hole and a problem that smeartends to occur even in the case of the laser processing by heat curing.

[0009] Japanese Patent Application Laid-Open Nos. 181458/1996 and236943/1996 disclose a technique in which a bismaleimide.triazine resin(BT resin) or thermosetting type poly(phenylene ether) (PPE) resin isused as an interlayer insulating material. Both resins are excellent inheat resistance and dielectric properties but have involved a problemthat the formation of a via hole is difficult, since it is difficult toimpart photosensitivity to the resins. In the case of thebismaleimide.triazine resin in particular, there has been a problem thatinsulation reliability is lowered in an accelerated durability test athigh temperature and high humidity because of its high waterabsorptivity, and so the resin is poor in durability.

[0010] By the way, a thermoplastic norbornene resin which is acycloolefin resin is known to be a material having excellent dielectricproperties and low water absorption property and exhibit excellentelectrical properties when it is used in a printed wiring board. Forexample, Japanese Patent Application Laid-Open No. 29191/1987 disclosesa process for producing a circuit board by impregnating a glass clothwith a thermoplastic norbornene resin obtained by additioncopolymerization of a norbornene monomer and ethylene and then curingthe resin with a peroxide, while Japanese Patent Application Laid-OpenNo. 27412/1987 discloses a method in which an epoxy group-containingthermoplastic norbornene resin obtained by graft-reacting an additioncopolymer of ethylene and a norbornene monomer with allyl glycidyl etheris used as an insulating material. However, these process and methodhave involved a problem that the glass transition temperature of eachresin is low, and its heat resistance is insufficient, because thecontent of the norbornene monomer unit is low, and so an interlayerinsulating film undergoes deformation or softening upon high-densitypackaging of semiconductor parts, and yield of the packaging is lowered.

[0011] As described above, any insulating material satisfying all therequired properties of the ability to form minute via holes, high heatresistance, low water absorption property and excellent dielectricproperties has heretofore not been proposed.

[0012] In the requirements of high-density assembly of an electroniccircuit and speeding up of a digital circuit, said both circuits beingused in computers and information communication, a high-density regionwhich cannot be accommodated by the conventional plated through-holemulti-layer board produced from a double-sided copper-clad laminate isrequired in a field of printed wiring boards used in these circuits.

[0013] Therefore, attention has been paid to a build-up process in whichan interlayer-connecting via hole is formed in each wiring layer tosuccessively connect wiring layers. The build-up process includes aphoto type using a photosensitive insulating material and a laser typeusing a thermosetting insulating material. It has heretofore been mainlyconducted to successively laminate layers while applying a varnish withany of these insulating materials dissolved in a solvent to a substrate,curing the varnish, forming via holes and forming a wiring pattern.

[0014] However, a process in which a curable resin such as an epoxyresin used in the above-described photosensitive or thermosettinginsulating material is formed into a film in advance, and the film islaminated on a substrate in a tack-free and semi-cured dry film state(B-stage state) has been already put to practical use in recent yearsfor the purpose of simplifying such complicated processes as describedabove and enhancing handling property.

[0015] However, the conventional dry film can simplify the process inthe lamination on the substrate compared with the coating of thesolution, but has involved a problem that a process for forming the filmis complicated for reasons of semi-curing a liquid epoxy monomer inadvance to form the tack-free film, and after all the dry film is notrelated to the simplification of the whole process. In addition, such adry film of the semi-cured state tends to be affected by temperature,light and the like and it is hence necessary to take care to store orhandle the film.

[0016] Further, in the field of printed wiring boards of electronicapparatus used in computers and information communication, it is ofurgent necessity to establish a build-up laminating process capable offorming wiring (wiring pitch, interlayer-connecting via holes) of highdensity in a region which has been impossible of achievement by theconventional plated through-hole method by drilling. A process in whicha build-up multi-layer laminate is produced while applying athermosetting poly(phenylene ether) resin excellent in heat resistance,low moisture absorption property and dielectric properties and the liketo a copper foil and heat-setting the resin by heating and pressing hasheretofore been disclosed in Japanese Patent Application Laid-Open No.1728/1997. However, the resistance to chemicals such as acids andalkalis of the thermosetting poly(phenylene ether) resin is notsufficient though it is excellent. Therefore, the surface of aninsulating layer is slightly dissolved upon etching of the copper foilor a chemical treatment for removal of smear after the formation ofinterlayer-connecting via holes in the production of the build-uplaminate, so that the anchor effect of a rough surface is too lowered tosufficiently ensure adhesion property to a plating layer and adhesionproperty between the insulating layers. There has hence been a problemthat reliability as a laminated board is greatly lowered. In order tosolve this problem, a surface roughening treatment must be conductedagain before the formation of the plating layer, and so the processbecomes complicated. Accordingly, it has heretofore been difficult toprovide a build-up multi-layer laminate which can be produced by asimple process and has sufficient reliability even when a materialsatisfying the requirements of high heat resistance and low dielectricproperties is used.

DISCLOSURE OF THE INVENTION

[0017] It is an object of the present invention to provide an interlayerinsulating material for high-density assembly boards such as bare chipmounting, which has excellent properties in the ability to form minutevia holes, heat resistance, low water absorption property and dielectricproperties, a high-density assembly board having an interlayerinsulating film formed with such an interlayer insulating material, anda semiconductor package using the high-density assembly board.

[0018] Another object of the present invention is to provide a dry filmexcellent in shelf stability, productivity, and forming and processingability, and a laminate making use of the dry film.

[0019] A further object of the present invention is to provide a processfor efficiently produce a build-up multi-layer laminate which isexcellent in chemical resistance and can ensure sufficient adhesionproperty and so can achieve high reliability, and materials to be usedin the process.

[0020] The present inventors have carried out an extensive investigationwith a view toward solving the above-described problems. As a result, ithas been found that when an insulating material comprising a cycloolefinpolymer containing at least 50 mol % of a repeating unit derived from acycloolefin monomer is used, an interlayer insulating film which canwithstand heat generated by high-density assembly and high-densitymounting such as bare chip mounting can be provided. In this interlayerinsulating film, interlayer-connecting via holes at most 200 μm indiameter can be formed with ease. The cycloolefin polymer has a glasstransition temperature of generally at least 100° C. and is henceexcellent in heat resistance.

[0021] It has also been found that the cycloolefin polymer is a materialexcellent in the ability to form minute via holes for reasons of thefact that (1) it is excellent in light transmittance, and so a film canbe efficiently cured up to the bottom thereof upon the formation of viaholes by photo-setting, (2) it is excellent in chemical resistance, andso the wall surface of each via hole is hard to swell, and (3) it iseasy to control sensitivity upon laser processing because absorption islittle in the polymer itself, and the polymer is easy to be decomposedto produce no smear. The cycloolefin polymer is best in low waterabsorption property and dielectric properties compared with theconventional materials, and deterioration of these properties issuppressed to a very small extent because photosensitivity and adhesionproperty can be imparted by introducing a polar group, thereby providinga high-density assembly board extremely excellent in insulationreliability, speeding up and high-frequency characteristics.

[0022] The present inventors have also carried out an extensiveinvestigation with a view toward developing a dry film having excellentvarious properties. As a result, it has been found that when a curableresin composition comprising a polymer having a number average molecularweight of 1,000 to 1,000,000 and a hardener is used to form a dry film,the film becomes tack-free without semi-curing the film because thepolymer is not liquid, so that the dry film can be produced with highproductivity by a simple process, and the shelf stability of the dryfilm is also enhanced. When the dry film is used to produce a build-upmulti-layer laminate, forming and processing ability is also enhancedbecause handling is easy.

[0023] The present inventors have further carried out an extensiveinvestigation with a view toward developing a process for efficientlyproducing a build-up multi-layer laminate, and materials to be used insuch a process. As a result, it has been found that when a cycloolefinpolymer is used as a resin film of a resin-attached metal foil, themetal foil becomes excellent in chemical resistance and low waterabsorption property and moreover adhesion property to a plating layerafter the formation of a wiring circuit or removal of smear and adhesionproperty upon build-up laminating can be sufficiently ensured to theresin-attached metal foil, so that the reliability of an insulatinglayer is enhanced, and the build-up laminating can be conducted withease because a complicated surface roughening treatment is unnecessary.

[0024] According to the present invention, there is thus provided aninterlayer insulating material for a high-density assembly board havinginterlayer-connecting via holes at most 200 μm in diameter, comprising acycloolefin polymer containing at least 50 mol % of a repeating unitderived from a cycloolefin monomer.

[0025] According to the present invention, there is also provided ahigh-density assembly board having interlayer-connecting via holes atmost 200 μm in diameter, wherein an interlayer insulating film of theboard comprises a cycloolefin polymer containing at least 50 mol % of arepeating unit derived from a cycloolefin monomer. According to thepresent invention, there is provided a semiconductor package making useof the high-density assembly board.

[0026] According to the present invention, there is further provided adry film formed from a curable resin composition comprising a polymerhaving a number average molecular weight within a range of 1,000 to1,000,000 as measured by gel permeation chromatography, and a hardener.According to the present invention, there is provided a process forproducing a dry film, the process comprising the steps of applying thecurable resin composition to a substrate and removing an organic solventunder conditions that a curing reaction of the curable resin compositionis not caused to completely proceed. According to the present invention,there is provided a laminate comprising an insulating layer formed withthe dry film and a conductive layer formed on the surface of theinsulating layer. According to the present invention, there are provideda multi-layer laminate further comprising each at least one insulatinglayer formed with the dry film and conductive layer, wherein theconductive layers are connected to each other by forminginterlayer-connecting via holes in the insulating layer provided betweenthem, and a production process thereof.

[0027] According to the present invention, there is still furtherprovided a resin-attached metal foil obtained by forming a film of acycloolefin polymer on one side of a metal foil. According to thepresent invention, there is provided a laminate obtained by laminatingthe resin-attached metal foil with the side of the resin film turnedinside. According to the present invention, there is provided a processfor producing a build-up multi-layer laminate, the process comprising astep (A) of forming a wiring pattern on the metal foil side of thelaminate and a step (B) of laminating the resin-attached metal foil onthe wiring pattern with the side of the resin film turned inside andthen forming a wiring pattern in the same manner as in the step (A),wherein the step (B) is repeated at least once.

[0028] The present invention has been led to completion on the basis ofthese findings.

BEST MODE FOR CARRYING OUT THE INVENTION

[0029] [Cycloolefin Polymer]

[0030] The cycloolefin polymer useful in the practice of the presentinvention is a polymer containing a repeating unit derived from acycloolefin monomer in the whole repeating unit of the polymer. Examplesof the cycloolefin monomer include alicyclic monomers having anorbornene ring, monocyclic cycloolefins and cyclic conjugated dienes.These cycloolefin monomers may be used either singly or in anycombination thereof, and may be copolymerized with anothercopolymerizable monomer. The cycloolefin polymer preferably contains arepeating unit derived from the cycloolefin monomer as a principalrepeating unit. The repeating unit derived from the cycloolefin monomerincludes not only the repeating unit of the cycloolefin, but alsomodified units of this repeating unit. Modifications includehydrogenation and graft modification by a polar group-containingunsaturated compound.

[0031] No particular limitation is imposed on the bonding style of thecycloolefin monomer so far as a cyclic structure can be introduced in amain chain, and it may be either addition polymerization or ring-openingpolymerization. Examples of the cycloolefin polymer include:

[0032] (1) addition polymers obtained by addition-polymerizing acarbon-carbon unsaturated bond in an alicyclic monomer having anorbornene ring, such as norbornene, ethylidene-norbornene,dicyclopentadiene or tetracyclododecene;

[0033] (2) addition copolymers obtained by addition-copolymerizing analicyclic monomer having a norbornene ring and an unsaturated monomersuch as an α-olefin;

[0034] (3) addition polymers obtained by addition-polymerizing acarbon-carbon unsaturated bond in a monocyclic cycloolefin such ascyclopentene or cyclohexene;

[0035] (4) addition polymers obtained by subjecting a cyclic conjugateddiene such as cyclohexadiene to 1,4-addition polymerization;

[0036] (5) ring-opening polymers obtained by ring-opening polymerizationof an alicyclic monomer having a norbornene ring; and

[0037] (6) hydrogenated products thereof.

[0038] The cycloolefin polymer used in the present invention ispreferably excellent in heat resistance. In this respect, thecycloolefin polymer is preferably a thermoplastic norbornene resin,particularly, a thermoplastic saturated norbornene resin such as anaddition (co)polymer comprising an alicyclic monomer (i.e., norbornenemonomer) having a norbornene ring as a main component, or a hydrogenatedproduct of a ring-opening polymer of the norbornene monomer.

[0039] The cycloolefin polymer desirably contains a repeating unitderived from the norbornene monomer in a proportion of generally atleast 50 mol %, preferably at least 70 mol %, more preferably at least80 mol % based on the whole repeating unit of the polymer. Thecycloolefin polymer is desirably a polymer having a glass transitiontemperature (Tg) of generally at least 100° C., preferably at least 120°C., more preferably at least 140° C. as measured by a differentialscanning calorimeter (DSC). In the case where higher heat resistance isrequired, the cycloolefin polymer is a polymer having a Tg of generallyat least 160° C., preferably at least 180° C., more preferably at least200° C. When the glass transition temperature of the cycloolefin polymerfalls within the above range, an insulating film formed with the polymerundergoes neither softening nor deformation by heat and pressure uponmounting semiconductor parts on the insulating film, and so such apolymer is preferred.

[0040] The molecular weight of the cycloolefin polymer used in thepresent invention is within a range of 1,000 to 1,000,000, preferably3,000 to 500,000, more preferably 5,000 to 300,000, most preferably10,000 to 200,000 when expressed by a number average molecular weight(Mn) in terms of polystyrene as measured by gel permeationchromatography (GPC).

[0041] If the number average molecular weight is extremely low, thestrength of an insulating film or dry film formed from the cycloolefinpolymer is lowered, which forms the cause of cracking. If the numberaverage molecular weight is extremely high on the other hand, theviscosity of the polymer becomes too high, and so its forming or moldingability and processability are deteriorated. It is hence not preferableto use a polymer having such a too low or high molecular weight. Whenthe number average molecular weight falls within the above range, thestrength of the resulting insulating film or dry film and the viscosityand processability of the polymer are moderately balanced with eachother, and so such a polymer is particularly preferred.

[0042] The cycloolefin polymer preferably contains a polar group(functional group) for the purpose of, for example, impartingphotosensitivity and enhancing the adhesion property to metal wiring andthe like. Methods for introducing the polar group into the cycloolefinpolymer include a method of modifying the cycloolefin polymer and amethod of (co)polymerizing a cycloolefin monomer having a polar group.

[0043] In order to yield excellent property values as an insulatingmaterial, the cycloolefin polymer used in the present inventionpreferably has the following physical property values:

[0044] Water Absorptivity:

[0045] It is desirable for the cycloolefin polymer to have a waterabsorptivity of generally at most 1%, preferably at most 0.5%, morepreferably at most 0.3%. In a field of which a lower water absorptivityis required, the polymer desirably has a water absorptivity of generallyat most 0.1%, preferably at most 0.05%, more preferably at most 0.02%.When the water absorptivity is low, the resulting insulating film ishard to absorb moisture, and so ions in a metal wiring layer isdifficult to be dissolved out, and the insulation reliability of thefilm is enhanced.

[0046] Dielectric Constant and Dielectric Loss Tangent:

[0047] The dielectric constant of the cycloolefin polymer is generallyat most 4.0 as measured at a frequency of 1 MHz. However, in the casewhere a lower dielectric constant is desired, it is desirable for thepolymer to have a water absorptivity of generally at most 3.0,preferably at most 2.5, more preferably at most 2.3. The dielectric losstangent of the cycloolefin polymer is generally at most 0.1 as measuredat a frequency of 1 MHz. However, in a field of which a lower dielectricloss tangent is required, the polymer desirably has a dielectric losstangent of generally at most 0.01, preferably at most 0.005, morepreferably at most 0.0005. Both dielectric constant and a dielectricloss tangent are as low as possible in the stage of the polymer. Whenthese values are small, the transmission rate of data between wiringlayers is enhanced, and transmission loss and generation of heat lessen.

[0048] [Cycloolefin Monomer]

[0049] No particular limitation is imposed on the cycloolefin monomerused as a principal component of the cycloolefin polymer so far as ithas a cyclic hydrocarbon compound having a carbon-carbon unsaturatedbond. However, the principal monomers include (1) alicyclic monomers(norbornene monomers) having a norbornene ring, (2) monocycliccycloolefin monomers and (3) cyclic conjugated diene monomers.

[0050] (1) Alicyclic Monomer Having a Norbornene Ring:

[0051] The alicyclic monomers having a norbornene ring are alicyclicmonomers having a norbornene ring described in Japanese PatentApplication Laid-Open Nos. 320268/1993 and 36224/1990. These alicyclicmonomers having a norbornene ring may be used either singly or in anycombination thereof.

[0052] The alicyclic monomer having a norbornene ring may be any of (a)a monomer having no other unsaturated bond than a carbon-carbonunsaturated bond participating in a polymerization reaction, (b) amonomer having another unsaturated bond in addition to a carbon-carbonunsaturated bond participating in a polymerization reaction, (c) amonomers having an aromatic ring, and (d) a monomer having a polargroup.

[0053] (a) Specific examples of the monomer having no other unsaturatedbond than a carbon-carbon unsaturated bond participating in apolymerization reaction include bicyclo[2.2.1]hept-2-ene derivativessuch as bicyclo[2.2.1]hept-2-ene, 5-methylbicyclo[2.2.1]hept-2-ene,5-ethylbicyclo[2.2.1]hept-2-ene, 5-butylbicyclo[2.2.1]-hept-2-ene,5-hexylbicyclo[2.2.1]hept-2-ene and 5-decylbicyclo[2.2.1]hept-2-ene;tetracyclo[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene derivatives such astetracyclo[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene,8-methyltetracyclo[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene and8-ethyltetracyclo[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene;tricyclo[4.3.1^(2,5).0]-dec-3-ene; and bicyclo[2.2.1]hept-2-enederivatives having a cyclic substituent group, such as5-cyclohexylbicyclo[2.2.1]hept-2-ene and5-cyclopentyl-bicyclo[2.2.1]hept-2-ene.

[0054] (b) Specific examples of the monomer having another unsaturatedbond in addition to a carbon-carbon unsaturated bond participating in apolymerization reaction include bicyclo[2.2.1]hept-2-ene derivativeshaving an unsaturated bond outside its ring, such as5-ethylidenebicyclo[2.2.1]hept-2-ene, 5-vinylbicyclo[2.2.1]-hept-2-eneand 5-propenylbicyclo[2.2.1]hept-2-ene;tetracyclo[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene derivatives having anunsaturated bond outside its ring, such as8-methylidenetetracyclo[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene,8-ethylidenetetracyclo[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene,8-vinyl-tetracyclo[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene and8-propenyl-tetracyclo[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene;tricyclo-[4.3.1^(2,5).0]-dec-3,7-diene; and bicyclo[2.2.1]hept-2-enederivatives having a cyclic substituent group with an unsaturated bond,such as 5-cyclohexenylbicyclo[2.2.1]-hept-2-ene and5-cyclopentenylbicyclo[2.2.1]-2-ene.

[0055] (c) Specific examples of the monomer having an aromatic ringinclude 5-phenylbicyclo[2.2.1]hept-2-ene,tetracyclo[6.5.1^(2,5).0^(1,6).0^(8,13)]tridec-3,8,10,12-tetraene (alsoreferred to as 1,4-methano-1,4,4a,9a-tetrahydrofluorene) andtetracyclo[6.6.1^(2,5).0^(1,6).0^(8,13)]tetradec-3,8,10,12-tetraene(also referred to as 1,4-methano-1,4,4a,5,10,10a-hexahydroanthracene).

[0056] (d) Specific examples of the monomer having a polar group includebicyclo[2.2.1]hept-2-ene derivatives having at least one substituentgroup containing an oxygen atom, such as5-methoxycarbonylbicyclo[2.2.1]hept-2-ene,5-ethoxycarbonylbicyclo[2.2.1]hept-2-ene,5-methyl-5-methoxycarbonylbicyclo[2.2.1]hept-2-ene,5-methyl-5-ethoxycarbonylbicyclo[2.2.1]hept-2-ene,bicyclo-[2.2.1]hept-5-enyl-2-methylpropionate,bicyclo[2.2.1]hept-5-enyl-2-methyloctanoate,bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylic acid anhydride,5-hydroxymethylbicyclo-[2.2.1]hept-2-ene,5,6-di(hydroxymethyl)bicyclo-[2.2.1]hept-2-ene,5-hydroxyisopropylbicyclo[2.2.1]hept-2-ene and5,6-dicarboxybicyclo[2.2.1]hept-2-ene;tetracyclo-[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene derivatives having atleast one substituent group containing an oxygen atom, such as8-methoxycarbonyltetracyclo[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene,8-methyl-8-methoxycarbonyltetracyclo[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene,8-hydroxymethyltetracyclo[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene and8-carboxytetracyclo[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene; andbicyclo[2.2.1]hept-2-ene derivatives having at least one substituentgroup containing a nitrogen atom, such as5-cyanobicyclo[2.2.1]hept-2-ene andbicyclo[2.2.1]hept-2-ene-5,6-dicarboxylic acid imide.

[0057] Further, alicyclic monomers having a norbornene ring with analkyl substituent group having at least 4 carbon atoms may be mentionedin common to all the alicyclic monomers having a norbornene ring.

[0058] (2) Monocyclic Cycloolefin Monomer:

[0059] The monocyclic cycloolefin monomers are cyclic compounds having acarbon-carbon double bond in their rings. Specific examples thereofinclude cyclobutene, cyclopentene, cyclohexene and cyclooctene (JapanesePatent Application Laid-Open No. 66216/1989). These monocycliccycloolefin monomers may be used either singly or in any combinationthereof.

[0060] (3) Cyclic Conjugated Diene Monomer:

[0061] The cyclic conjugated diene monomers are cyclic compounds havinga conjugated carbon-carbon double bond in their rings. Specific examplesthereof include 1,3-cyclopentadiene, 1,3-cyclohexadiene,1,3-cycloheptadiene and 1,3-cyclooctadiene (Japanese Patent ApplicationLaid-Open No. 258318/1995). These cyclic conjugated diene monomers arecyclic compounds may be used either singly or in any combinationthereof.

[0062] In the case where the cycloolefin polymer is an addition(co)polymer, an alicyclic monomer having a norbornene ring with along-chain alkyl substituent group having at least 4 carbon atoms, suchas 6-butylbicyclo-[2.2.1]hept-2-ene, 6-hexylbicyclo[2.2.1]hept-2-ene or6-decylbicyclo[2.2.1]hept-2-ene, is preferably copolymerized in order toimpart flexibility to the resulting material. In the case where thecycloolefin polymer is a ring-opening polymer, an alicyclic monomerhaving a norbornene ring composed of a heterocycle of at least tworings, such as tetracyclo[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene,8-methyl-tetracyclo[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene or8-ethyl-tetracyclo[4.4.1^(2,5).1^(7,10).0]-dodec-3-ene, an alicyclicmonomer having a norbornene ring composed of a heterocycle of at leastthree rings, such as a hexacycloheptadecene monomer, or1,4-methano-1,4,4a,9a-tetrahydrofluorene is preferably used from theviewpoint of heat resistance.

[0063] As unsaturated monomers copolymerizable with the cycloolefinmonomer, may be mentioned α-olefins having 2 to 12 carbon atoms, such asethylene, propylene, 1-butene and 4-methyl-1-pentene; styrene andderivatives thereof such as styrene, α-methylstyrene, p-methylstyreneand p-chlorostyrene; linear conjugated dienes such as 1,3-butadiene andisoprene; vinyl ethers such as ethyl vinyl ether and isobutyl vinylether; and carbon monoxide. Such unsaturated monomers are notparticularly limited to the above monomers so far as they arecopolymerizable with the cycloolefin monomer. In the case where thealicyclic monomer having a norbornene ring is copolymerized with anotherunsaturated monomer, a vinyl compound such as one of the above-mentionedα-olefins is preferably used as said another unsaturated monomer.

[0064] [Polar Group-Containing Cycloolefin Polymer]

[0065] The cycloolefin polymer preferably contains a polar group(functional group) for the purpose of, for example, enhancing theadhesion property to a metal conductor layer in particular, impartingphotosensitivity, making it possible to cure the polymer by variousmethods, raising crosslinking density, improving compatibility withother compounding agents, resins and the like, and enhancing heatresistance.

[0066] No particular limitation is imposed on the polar group in thepolar group-containing cycloolefin polymer used in the present inventionso far as it is a polar group which is capable of enhancing the adhesionproperty to metals and other resin materials and has a function ofbecoming a curing point upon a curing reaction. Examples thereof includeepoxy, carboxyl, hydroxyl, ester, silanol, amino, nitrile, halogeno,acyl and sulfonic groups. Of these, the epoxy, carboxyl, hydroxyl andester groups are particularly preferred from the viewpoint of making itpossible to impart adhesion property and photosensitivity at a lowmodification rate.

[0067] The polar group-containing cycloolefin polymer can be obtained byintroducing a polar group such as an epoxy, carboxyl, hydroxyl or estergroup into the cycloolefin polymer, for example, in accordance with oneof the following three processes:

[0068] (1) a process in which a polar group-containing unsaturatedcompound is added to the cycloolefin polymer by a graft reaction,

[0069] (2) a process in which a polar group is directly introduced intoa carbon-carbon unsaturated bond in the cycloolefin polymer, and

[0070] (3) a process in which a polar group-containing cycloolefinmonomer is copolymerized with the cycloolefin polymer.

[0071] The respective processes for introducing a polar group willhereinafter be described in detail.

[0072] (1) Graft Reaction of Polar Group-Containing UnsaturatedCompound:

[0073] The polar group-containing cycloolefin polymer can be obtained byreacting the cycloolefin polymer with a polar group-containingunsaturated compound in the presence of an organic peroxide. Noparticular limitation is imposed on the polar group-containingunsaturated compound. However, epoxy group-containing unsaturatedcompounds, carboxyl group-containing unsaturated compounds, hydroxylgroup-containing unsaturated compounds, silyl group-containingunsaturated compounds, etc. are preferred because photosensitivity canbe imparted in a small amount, and adhesion property can be improved.

[0074] Examples of the epoxy group-containing unsaturated compoundsinclude glycidyl esters such as glycidyl acrylate, glycidyl methacrylateand glycidyl p-styryl-carboxylate; mono- or polyglycidyl esters ofunsaturated polycarboxylic acids such asendo-cis-bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylic acid andendo-cis-bicyclo[2,2,1]-hept-5-ene-2-methyl-2,3-dicarboxylic acid;unsaturated glycidyl ethers such as allyl glycidyl ether, 2-methyl-allylglycidyl ether, glycidyl ether of o-allylphenol, glycidyl ether ofm-allylphenol and glycidyl ether of p-allylphenol; and2-(o-vinylphenyl)ethylene oxide, 2-(p-vinylphenyl)ethylene oxide,2-(o-allylphenyl)ethylene oxide, 2-(p-allylphenyl)ethylene oxide,2-(o-vinylphenyl)-propylene oxide, 2-(p-vinylphenyl)propylene oxide,2-(o-allylphenyl)propylene oxide, 2-(p-allylphenyl)propylene oxide,p-glycidylstyrene, 3,4-epoxy-1-butene, 3,4-epoxy-3-methyl-1-butene,3,4-epoxy-1-pentene, 3,4-epoxy-3-methyl-1-pentene, 5,6-epoxy-1-hexene,vinylcyclohexene monoxide and allyl-2,3-epoxycyclopentyl ether. Ofthese, the allyl glycidyl esters and allyl glycidyl ethers arepreferred, with the allyl glycidyl ethers being particularly preferred,in that such an epoxy group-containing unsaturated compound permitsgraft addition at a particularly high reaction rate. These epoxygroup-containing unsaturated compounds may be used either singly or inany combination thereof.

[0075] As examples of the carboxyl group-containing unsaturatedcompounds, may be mentioned compounds described in Japanese PatentApplication Laid-Open No. 271356/1993, such as acrylic acid, methacrylicacid, maleic acid, fumaric acid and itaconic acid. Derivatives of theunsaturated carboxylic acids may also be included in the carboxylgroup-containing unsaturated compounds. As examples of the unsaturatedcarboxylic acid derivatives, may be mentioned halides, amides, imides,anhydrides (for example, maleic anhydride) and esters of unsaturatedcarboxylic acids.

[0076] Examples of the hydroxyl group-containing unsaturated compoundsinclude allyl alcohol, 2-allyl-6-methoxyphenol,4-allyloxy-2-hydroxybenzophenone, 3-allyloxy-1,2-propanediol,2-allyldiphenol, 3-buten-1-ol, 4-penten-1-ol and 5-hexen-1-ol.

[0077] Examples of the silyl group-containing unsaturated compoundsinclude chlorodimethylvinylsilane, trimethyl-silylacetylene,5-trimethylsilyl-1,3-cyclopentadiene, 3-trimethylsilylallyl alcohol,trimethylsilyl methacrylate, 1-trimethylsilyloxy-1,3-butadiene,1-trimethylsilyloxy-cyclopentene, 2-trimethylsilyloxyethyl methacrylate,2-trimethylsilyloxyfuran, 2-trimethylsilyloxypropene,allyloxy-t-butyldimethylsilane and allyloxytrimethyl-silane.

[0078] As the organic peroxide, for example, organic peroxides, organicperesters, etc. may be preferably used. As specific examples of such anorganic peroxide, may be mentioned benzoyl peroxide, dichlorobenzoylperoxide, dicumyl peroxide, di-tert-butyl peroxide,2,5-dimethyl-2,5-di(peroxide benzoate)hexyne-3, 1,4-bis(tert-butylperoxyisopropyl)benzene, lauroyl peroxide, tert-butyl peracetate,2,5-dimethyl-2,5-di(tert-butyl peroxy)hexyne-3,2,5-dimethyl-2,5-di(tert-butyl peroxy)hexane, tert-butyl perbenzoate,tert-butyl perphenylacetate, tert-butyl perisobutyrate, tert-butylper-sec-octoate, tert-butyl perpivalate, cumyl perpivalate andtert-butyl perdiethylacetate.

[0079] In the present invention, azo compounds may also be used as theorganic peroxides. As specific examples of the azo compounds, may bementioned azobisisobutyronitrile and dimethyl azoisobutyrate.

[0080] Of these, benzoyl peroxide, and dialkyl peroxides such as dicumylperoxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxide)hexyne-3, 2,5-dimethyl-2,5-di(tert-butyl peroxy)hexane and1,4-bis(tert-butyl peroxyisopropyl)benzene are preferably used as theorganic peroxides.

[0081] These organic peroxides may be used either singly or in anycombination thereof. A proportion of the organic peroxide used isgenerally within a range of 0.001 to 30 parts by weight, preferably 0.01to 20 parts by weight, more preferably 0.1 to 10 parts by weight per 100parts by weight of the unmodified cycloolefin polymer in terms of acharged proportion upon the reaction. The amount of the organic peroxideused within this range is preferred because the reaction rate of thepolar group-containing unsaturated compound, and various properties ofthe resulting polar group-containing polymer, such as water absorptivityand dielectric properties are balanced with one another at a high level.

[0082] No particular limitation is imposed on the graft-modifyingreaction, and the reaction may be carried out in accordance with amethod known per se in the art. The reaction is conducted at atemperature of generally 0 to 400° C., preferably 60 to 350° C. Thereaction time is generally within a range of 1 minute to 24 hours,preferably 30 minutes to 10 hours. After completion of the reaction, apoor solvent such as methanol is added in a great amount to the reactionsystem to deposit a polymer formed, and the polymer is collected byfiltration, washed and then dried under reduced pressure, whereby agraft-modified polymer can be obtained.

[0083] (2) Direct Modification of Carbon-Carbon Unsaturated Bond:

[0084] The polar group-containing cycloolefin polymer can be obtained byintroducing a polar group by modifying an olefinic carbon-carbonunsaturated bond in the cycloolefin polymer to add the polar group or bybonding a compound having a polar group to the olefinic carbon-carbonunsaturated bond.

[0085] With respect to a process for introducing the polar group, such aprocess as described in Japanese Patent Application Laid-Open No.172423/1994 may be used. Specifically, a process in which an epoxygroup, carboxyl group, hydroxyl group or the like is introduced by amethod of oxidizing the olefinic unsaturated bond, a method of adding acompound having at least one polar group in its molecule to the olefinicunsaturated bond, or the like is mentioned.

[0086] (3) Copolymerization of Polar Group-Containing Olefin Monomer:

[0087] No particular limitation is imposed on the polar group-containingcycloolefin monomer. However, as examples of the monomer having a polargroup, may be mentioned the monomers having a polar group mentioned in(d) in the above description as to the monomers. Of these monomers,monomers having a hydroxyl, carboxyl or ester group, such as5-hydroxymethylbicyclo[2.2.1]hept-2-ene,5-hydroxy-isopropylbicyclo[2.2.1]hept-2-ene,5-methoxycarbonyl-bicyclo[2.2.1]hept-2-ene,8-methoxycarbonyltetracyclo-[4.4.0.1^(2,5).1^(7,10).0]-dodec-3-ene and5,6-dicarboxybicyclo-[2.2.1]hept-2-ene are preferred from the viewpointof easy copolymerization. With respect to a catalyst and apolymerization process, a polymerization catalyst and a polymerizationprocess for the alicyclic monomer having a norbornene ring may be used.

[0088] (4) Rate of Introduction of Polar Group:

[0089] The rate of introduction of the polar group in the polargroup-containing cycloolefin polymer is suitably selected as necessaryfor the end application intended. However, it is generally within arange of 0.1 to 100 mol %, preferably 1 to 50 mol, more preferably 5 to30 mol % based on the total number of monomer units in the polymer. Whenthe rate of introduction of the polar group in the polargroup-containing cycloolefin polymer falls within this range, the waterabsorptivity, dielectric properties and bond strength to a metalconductor layer are balanced with one another at a high level.

[0090] The rate of introduction of the polar group (rate ofmodification: mol %) is represented by the following equation (1):

Rate of introduction of the polar group=(X/Y)×100  (1)

[0091] wherein

[0092] X: (a) the total number of moles of modifying residue introducedby a graft monomer,

[0093] (b) (the total number of moles of unsaturated bond-containingmonomer)×(rate of addition of polar group to unsaturated bond), or

[0094] (c) the total number of moles of the polar group-containingmonomer

[0095]  (all, determined by ¹H—NMR);

[0096] Y: the total number of monomer units in the polymer (weightaverage molecular weight of the polymer/average molecular weight of themonomer).

[0097] [Curable Cycloolefin Polymer Composition]

[0098] The cycloolefin polymers used in the present invention can beformulated into curable cycloolefin polymer compositions by adding ahardener thereto. By converting the cycloolefin polymer into a curabletype, for example, the following advantages can be obtained. Namely, (1)when it is laminated on a metal foil, a difference in coefficient oflinear expansion between the metal foil and the resin layer becomessmall, and (2) sufficient heat resistance can be exhibited upon thefabrication of a build-up laminate, mounting of electronic parts and areliability test. No particular limitation is imposed on the hardener.However, (i) an organic peroxide, (ii) a hardener capable of exhibitingits effect by heat, (iii) a hardener capable of exhibiting its effect bylight, or the like is used.

[0099] No particular limitation is imposed on the method for curing thecurable cycloolefin polymer compositions. For example, the curing can beconducted by using heat, light, radiation and/or the like. The kind ofthe hardener is suitably selected according to such means. When theaddition (co)polymer of the alicyclic monomer having a norbornene ringor the hydrogenated product of the ring-opening (co)polymer has anaromatic ring, the ability to uniformly disperse various hardenerstherein becomes good.

[0100] Into the curable cycloolefin polymer compositions, a curing aid,a flame retardant, other compounding additives, etc. may be blended inaddition to the hardener if desired.

[0101] Hardener:

[0102] (1) Organic Peroxide:

[0103] Examples of the organic peroxide include ketone peroxides such asmethyl ethyl ketone peroxide and cyclohexanone peroxide; peroxyketalssuch as 1,1-bis(t-butyl peroxy)-3,3,5-trimethylcyclohexane and2,2-bis(t-butyl peroxy)butane; hydroperoxides such as t-butylhydroperoxide and 2,5-dimethylhexane-2,5-dihydroperoxide; dialkylperoxides such as dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3 and α,α′-bis(t-butyl peroxy-m-isopropyl)benzene; diacylperoxides such as octanoyl peroxide and isobutyryl peroxide; andperoxyesters such as peroxydicarbonate. Of these, the dialkyl peroxidesare preferred from the viewpoint of performance of the crosslinkedresin. The kind of the alkyl group can be changed according to thecuring temperature (forming or molding temperature).

[0104] No particular limitation is imposed on the amount of the organicperoxide blended. However, it is used within a range of generally 0.1 to30 parts by weight, preferably 1 to 20 parts by weight per 100 parts byweight of the cycloolefin polymer from the viewpoints of efficientlyconducting a crosslinking reaction, improving the physical properties ofthe resulting cured polymer, and being profitable. If the blendingamount is too little, the resulting composition becomes hard to undergocrosslinking, and so sufficient heat resistance and solvent resistancecannot be imparted to the composition. If the amount is too great on theother hand, the properties of the cured resin, such as water absorptionproperty and dielectric properties are deteriorated. It is hence notpreferred to use the organic peroxide in such a too small or greatamount. The blending amount within the above range is preferred becausethese properties are balanced with each other at a high level.

[0105] (2) Hardener Capable of Exhibiting its Effect by Heat:

[0106] No particular limitation is imposed on the hardener capable ofexhibiting its effect by heat so far as it can cause a curing reactionby heating. However, examples thereof include aliphatic polyamines,alicyclic polyamines, aromatic polyamines, bisazides, acid anhydrides,dicarboxylic acids, polyhydric phenols and polyamides.

[0107] Specific examples thereof include aliphatic polyamines such ashexamethylenediamine, triethylene-tetramine, diethylenetriamine andtetraethylenepentamine; alicyclic polyamines such as diaminocyclohexane,3(4),8(9)-bis(aminomethyl)tricyclo[5,2,1,0^(2,6)]decane,1,3-(diaminomethyl)cyclohexane, menthenediamine, isophorone-diamine,N-aminoethylpiperazine, bis(4-amino-3-methyl-cyclohexyl)methane andbis(4-aminocyclohexyl)methane; aromatic polyamines such as4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane,α,α′-bis(4-aminophenyl)-1,3-diisopropylbenzene,α,α′-bis(4-aminophenyl)-1,4-diisopropylbenzene, 4,4′-diaminodiphenylsulfone and m-phenylenediamine; bisazides such as4,4′-bisazidobenzal-(4-methyl)cyclohexanone, 4,4′-diazidochalcone,2,6-bis(4′-azidobenzal)cyclohexanone,2,6-bis(4′-azidobenzal)-4-methylcyclohexanone, 4,4′-diazidodiphenylsulfone, 4,4′-diazidodiphenylmethane and 2,2′-diazidostilbene; acidanhydrides such as phthalic anhydride, pyromellitic anhydride,benzophenonetetracarboxylic acid anhydride, nadic anhydride,1,2-cyclohexanedicarboxylic acid, maleic anhydride-modifiedpolypropylene and maleic anhydride-modified cycloolefin resins;dicarboxylic acids such as fumaric acid, phthalic acid, maleic acid,trimellitic acid and himic acid; polyhydric phenols such as phenolnovolak resins and cresol novolak resin; and polyamides such as nylon 6,nylon 66, nylon 610, nylon 11, nylon 612, nylon 12, nylon 46,methoxymethylated polyamide, polyhexa-methylenediamine terephthalamideand polyhexamethylene isophthalamide.

[0108] These hardeners may be used either singly or in any combinationthereof. Of these, the aliphatic polyamines and aromatic polyamines arepreferred for reasons of easy uniform dispersion. Further, the aromaticpolyamines from the viewpoint of excellent heat resistance, and thepolyhydric phenols from the viewpoint of excellent strength propertiesare particularly preferred. As needed, a hardening accelerator may alsobe blended to enhance the efficiency of the crosslinking reaction.

[0109] No particular limitation is imposed on the amount of the hardenerblended. From the viewpoints of being able to efficiently conduct acrosslinking reaction and improve the physical properties of theresulting crosslinked resin, and being profitable, however, it isgenerally within a range of 0.1 to 30 parts by weight, preferably 1 to20 parts by weight per 100 parts by weight of the cycloolefin polymer.If the amount of the hardener is too little, the resulting compositionbecomes hard to undergo crosslinking, and so sufficient heat resistanceand solvent resistance cannot be imparted to the composition. To thecontrary, any amount too great results in a crosslinked resin lowered inproperties such as water absorption property and dielectric properties.It is hence not preferred to use the hardener in any amount outside theabove range. The blending amount within the above range is preferredbecause these properties are balanced with each other at a high level.

[0110] As examples of the hardening accelerator, may be mentioned aminessuch as pyridine, benzyldimethylamine, triethanolamine, triethylamineand imidazoles. The hardening accelerator is added in order to regulatecuring rate and further enhance the efficiency of the crosslinkingreaction. No particular limitation is imposed on the amount of thehardening accelerator blended. However, it is used within a range ofgenerally 0.1 to 30 parts by weight, preferably 1 to 20 parts by weightper 100 parts by weight of the cycloolefin polymer. The blending amountof the hardening accelerator within this range is preferred becausecrosslinking density, dielectric properties, water absorptivity and thelike of the crosslinked resin are balanced with one another at a highlevel. Among others, imidazoles are preferred in that a cured resinexcellent in dielectric properties can be provided.

[0111] (3) Hardener Capable of Exhibiting its Effect by Light:

[0112] No particular limitation is imposed on the hardener capable ofexhibiting its effect by light so far as it is a photoreactive substancewhich reacts with the cycloolefin polymer by irradiation of actinic rayssuch as ultraviolet rays such as g rays, h rays or i rays, farultraviolet rays, X rays, or electron rays to form a crosslinkedcompound. However, examples thereof include aromatic bisazide compounds,photo-induced amine generators and photo-induced acid generators.

[0113] Specific examples of the aromatic bisazide compounds include4,4′-diazidochalcone, 2,6-bis(4′-azidobenzal)-cyclohexanone,2,6-bis(4′-azidobenzal)-4-methyl-cyclohexanone, 4,4′-diazidodiphenylsulfone, 4,4′-diazidobenzophenone, 4,4′-diazidophenyl,2,7-diazido-fluorene and 4,4′-diazidophenylmethane. These compounds maybe used either singly or in any combination thereof.

[0114] Specific examples of the photo-induced amine generators includeo-nitrobenzyloxycarbonylcarbamates,2,6-dinitrobenzyloxycarbonylcarbamates andα,α-dimethyl-3,5-dimethoxybenzyloxycarbonylcarbamates of aromatic aminesor aliphatic amines. More specifically, there may be mentionedo-nitrobenzyloxycarbonylcarbamates of aniline, cyclohexylamine,piperidine, hexamethylenediamine, triethylenetetramine,1,3-(diaminomethyl)cyclohexane, 4,4′-diaminodiphenyl ether,4,4′-diaminodiphenylmethane, phenylenediamine and the like. Thesecompounds may be used either singly or in any combination thereof.

[0115] The photo-induced acid generator is a substance which forms aBrφnsted acid or Lewis acid upon exposure to actinic rays. Examplesthereof include onium salts, halogenated organic compounds,quinonediazide compounds, α,α-bis(sulfonyl)diazomethane compounds,α-carbonyl-α-sulfonyl-diazomethane compounds, sulfone compounds, organicacid ester compounds, organic acid amide compounds and organic acidimide compounds. These compounds, which cleave upon exposure to theactinic rays to form an acid, may be used either singly or in anycombination thereof.

[0116] No particular limitation is imposed on the amount of thesephotoreactive compounds blended. From the viewpoints of being able toefficiently conduct the reaction with the polymer, not impairing thephysical properties of the resulting crosslinked resin, and beingprofitable, however, it is generally within a range of 0.1 to 30 partsby weight, preferably 1 to 20 parts by weight per 100 parts by weight ofthe cycloolefin polymer. If the amount of the photoreactive substanceblended is too little, the resulting composition becomes hard to undergocrosslinking, and so sufficient heat resistance and solvent resistancecannot be imparted to the composition. On the other hand, any amount toogreat results in a crosslinked resin lowered in properties such as waterabsorption property and dielectric properties. It is hence notpreferable to use the photoreactive compound in any amount outside theabove range. The blending amount within the above range is preferredbecause these properties are balanced with each other at a high level.

[0117] Curing Aid:

[0118] In the present invention, a curing aid (hardening aid) may beused for the purpose of more enhancing curability and the dispersibilityof the compounding additives.

[0119] No particular limitation is imposed on the curing aid. Publiclyknown compounds disclosed in Japanese Patent Application Laid-Open No.34924/1987 and the like may be used. Examples thereof includeoxime.nitroso type curing aids such as quinone dioxime, benzoquinonedioxime and p-nitrosophenol; maleimide type curing aids such asN,N-m-phenylenebismaleimide; allyl type curing aids such as diallylphthalate, triallyl cyanurate and triallyl isocyanurate; methacrylatetype curing aids such as ethylene glycol dimethacrylate andtrimethylolpropane trimethacrylate; and vinyl type curing aids such asvinyltoluene, ethylvinylbenzene and divinylbenzene. Of these, the allyltype curing aids and methacrylate type curing aids are preferred becausethey are easy to be uniformly dispersed.

[0120] The amount of the curing aid blended is suitably selectedaccording to the kind of the hardener used. However, it is generally 0.1to 10 parts by weight, preferably 0.2 to 5 parts by weight per part byweight of the hardener. If the amount of the curing aid blended is toolittle, the resulting composition becomes hard to undergo curing. On theother hand, any amount too great results in a crosslinked resin having apossibility that its electrical properties, moisture resistance and thelike may be deteriorated.

[0121] [Compounding Additives]

[0122] Various kinds of compounding additives may be added to thecycloolefin polymers and curable cycloolefin polymer compositionsaccording to the present invention if desired.

[0123] Flame Retardant:

[0124] A flame retardant is not an essential component. However, it ispreferred that the flame retardant be added to the cycloolefin polymercomposition when the thickness of an interlayer insulating film or dryfilm formed from the composition becomes great as a whole. No particularlimitation is imposed on the flame retardant. However, those whichundergo none of decomposition, denaturation and deterioration by thehardener are preferred. Halogen-containing flame retardants aregenerally used.

[0125] Various kinds of chlorine- or bromine-containing flame retardantsmay be used as the halogen-containing flame retardants. From theviewpoints of flameproofing effect, heat resistance upon forming ormolding, dispersibility in resins and influence on the physicalproperties of the resins, however, the following flame retardants may bepreferably used. Namely, preferable examples thereof includehexabromobenzene, pentabromo-ethylbenzene, hexabromobiphenyl,decabromodiphenyl, hexabromodiphenyl oxide, octabromodiphenyl oxide,decabromodiphenyl oxide, pentabromocyclohexane, tetrabromobisphenol Aand derivatives thereof [for example, tetrabromobisphenolA-bis(hydroxyethyl ether), tetrabromobisphenol A-bis(2,3-dibromopropylether), tetrabromobisphenol A-bis(bromoethyl ether), tetrabromobisphenolA-bis(allyl ether), etc.], tetrabromobisphenol S and derivative thereof[for example, tetrabromobisphenol S-bis(hydroxyethyl ether),tetrabromobisphenol S-bis(2,3-dibromopropyl ether), etc.],tetrabromophthalic anhydride and derivatives thereof [for example,tetrabromophthalimide, ethylenebistetrabromophthalimide, etc.],ethylenebis(5,6-dibromonorbornene-2,3-dicarboxyimide),tris-(2,3-dibromopropyl-1) isocyanurate, adducts ofhexachlorocyclopentadiene by Diels-Alder reaction, tribromophenylglycidyl ether, tribromophenyl acrylate, ethylenebistribromophenylether, ethylenebis-pentabromophenyl ether,tetradecabromodiphenoxybenzene, brominated polystyrene, brominatedpolyphenylene oxide, brominated epoxy resins, brominated polycarbonate,polypentabromobenzyl acrylate, octabromonaphthalene,hexabromocyclododecane, bis(tribromophenyl)fumaramide andN-methylhexabromodiphenylamine.

[0126] The amount of the flame retardant added is generally 3 to 150parts by weight, preferably 10 to 140 parts by weight, particularlypreferably 15 to 120 parts by weight per 100 parts by weight of thecycloolefin polymer.

[0127] As a flame retardant auxiliary for causing the flame retardant tomore effectively exhibit its flameproofing effect, for example, anantimonial flame retardant auxiliary such as antimony trioxide, antimonypentoxide, sodium antimonate or antimony trichloride may be used. Theseflame retardant auxiliaries are used in a proportion of generally 1 to30 parts by weight, preferably 2 to 20 parts by weight per 100 parts byweight of the flame retardant.

[0128] Curable Resin:

[0129] In the present invention, a curable resin such as an epoxy resinheretofore used may be blended for the purpose of, for example,improving viscosity characteristics upon heating and melting of a dryfilm, thereby controlling the viscosity of the dry film upon itsheating, melting and press-bonding.

[0130] As specific examples of curable resins, may be blended, forexample, the conventionally known curable resins such as thermosettingepoxy resins, photosensitive epoxy resins, polyimide resins,photosensitive polyimide resins, bismaleimide.triazine resins, phenolresins and phenol novolak resins.

[0131] Other Polymer Components:

[0132] In the present invention, rubbery polymers and otherthermoplastic resins may be blended into the cycloolefin polymers asneeded.

[0133] The rubbery polymers are polymers having a glass transitiontemperature of ordinary temperature (25° C.) or lower and includegeneral rubber-like polymers and thermoplastic elastomers. The Mooneyviscosity (ML₁₊₄, 100° C.) of such a rubbery polymer is suitablyselected as necessary for the end application intended and is generally5 to 200.

[0134] Examples of the rubber-like polymers include ethylene-α-olefintype rubbery polymers; ethylene-α-olefin-polyene terpolymer rubbers;copolymers of ethylene and an unsaturated carboxylic acid ester, such asethylene-methyl methacrylate copolymers and ethylene-butyl acrylatecopolymers; copolymers of ethylene and a fatty acid vinyl ester, such asethylene-vinyl acetate copolymers; polymers of acrylic acid alkyl esterssuch as ethyl acrylate, butyl acrylate, hexyl acrylate, 2-ethyl-hexylacrylate and lauryl acrylate; diene rubbers such as polybutadiene,polyisoprene, styrene-butadiene or styrene-isoprene random copolymers,acrylonitrile-butadiene copolymers, butadiene-isoprene copolymers,butadiene-alkyl (meth)acrylate copolymers, butadiene-alkyl(meth)acrylate-acrylonitrile terpolymers and butadiene-alkyl(meth)acrylate-acrylonitrile-styrene tetrapolymers; andbutylene-isoprene copolymers.

[0135] As examples of the thermoplastic elastomers, may be mentionedaromatic vinyl-conjugated diene block copolymers such asstyrene-butadiene block polymers, hydrogenated styrene-butadiene blockcopolymers, styrene-isoprene block copolymers and hydrogenatedstyrene-isoprene block copolymers, low crystalline polybutadiene resins,ethylene-propylene elastomers, styrene-grafted ethylene-propyleneelastomers, thermoplastic polyester elastomers, and ethylenic ionomerresins. Of these thermoplastic elastomers, the hydrogenatedstyrene-butadiene block copolymers and hydrogenated styrene-isopreneblock copolymers are preferred. As specific examples thereof, may bementioned those described in Japanese Patent Application Laid-Open Nos.133406/1990, 305814/1990, 72512/1991 and 74409/1991, etc.

[0136] Examples of the other thermoplastic resins include low densitypolyethylene, high density polyethylene, linear low densitypolyethylene, very low density polyethylene, ethylene-ethyl acrylatecopolymers, ethylene-vinyl acetate copolymers, polystyrene,poly(phenylene sulfide), poly(phenylene ether), polyamide, polyester,polycarbonate and cellulose triacetate.

[0137] These rubbery polymers and other thermoplastic resins may be usedeither singly or in any combination thereof. The blending amount thereofis suitably selected within limits not impeding the objects of thepresent invention. However, it is preferably at most 30 parts by weightfor reasons of not impeding the properties of the resulting insulatingmaterial.

[0138] Other Compounding Additives:

[0139] To the cycloolefin polymers and curable cycloolefin polymercompositions according to the present invention, may be added properamounts of other compounding additives such as heat stabilizers,weathering stabilizers, leveling agents, antistatic agents, slip agents,antiblocking agents, anti-fogging agents, lubricants, dyes, pigments,natural oil, synthetic oil, wax and organic or inorganic fillers asneeded.

[0140] Specific examples thereof include phenolic antioxidants such astetrakis[methylene-3(3,5-di-t-butyl-4-hydroxyphenyl) propionate]methane,alkyl β-(3,5-di-t-butyl-4-hydroxyphenyl)propionates and2,2′-oxamidobis-[ethyl-3(3,5-di-t-butyl-4-hydroxyphenyl) propionate];phosphoric stabilizers such as trisnonylphenyl phosphate,tris(2,4-di-t-butylphenyl) phosphate and tris(2,4-di-t-butylphenyl)phosphate; fatty acid metal salts such as zinc stearate, calciumstearate and calcium 12-hydroxy-stearate; polyhydric alcohol fatty acidesters such as glycerol monostearate, glycerol monolaurate, glyceroldistearate, pentaerythritol monostearate, pentaerythritol distearate andpentaerythritol tristearate; synthetic hydrotalcite; amine typeantistatic agents; leveling agents for paints, such asfluorine-containing nonionic surfactants, special acrylic resin typeleveling agents and silicone type leveling agents; coupling agents suchas silane coupling agents, titanate coupling agents, aluminum-containingcoupling agents and zircoaluminate coupling agents; plasticizers; andcolorants such as pigments and dyes.

[0141] As examples of the organic or inorganic fillers, may be mentionedsilica, diatomaceous earth, alumina, titanium oxide, magnesium oxide,pumice powder, pumice balloon, basic magnesium carbonate, dolomite,calcium sulfate, potassium titanate, barium sulfate, calcium sulfite,talc, clay, mica, asbestos, glass fibers, glass flake, glass beads,calcium silicate, montmorillonite, bentonite, graphite, aluminum powder,molybdenum sulfide, boron fibers, silicon carbide fibers, polyethylenefibers, polypropylene fibers, polyester fibers and polyamide fibers.

[0142] [Interlayer Insulating Material and High-Density Assembly Board]

[0143] (1) Varnish and Solvent:

[0144] The interlayer insulating material for high-density assemblyaccording to the present invention is generally used in the form of avarnish by dissolving the cycloolefin polymer or curable cycloolefinpolymer composition in a solvent.

[0145] Examples of the solvent used at this time include aromatichydrocarbons such as toluene, xylene and ethylbenzene; aliphatichydrocarbons such as n-pentane, hexane and heptane; alicyclichydrocarbons such as cyclohexane; and halogenated hydrocarbons such aschlorobenzene, dichlorobenzene and trichlorobenzene.

[0146] The solvent is used in an amount sufficient to uniformly dissolveor disperse the cycloolefin polymer and the individual componentsoptionally blended therein. The amount is generally controlled in such amanner that a solids concentration amounts to 1 to 80 wt. %, preferably5 to 60 wt. %, more preferably 10 to 50 wt. %.

[0147] In the present invention, the above-described varnish may also beused in the form of a sheet (film) formed by a solution casting processor a metal foil-attached film by coating a thin metal film such ascopper with the varnish. Further, the varnish may be used in the form ofa sheet (prepreg) by impregnating a reinforcing base material with thevarnish.

[0148] (2) High-Density Assembly Board:

[0149] The high-density assembly board according to the presentinvention is a board having via holes at most 200 μm in diameter and aninterlayer insulating film formed with the above-described insulatingmaterial. In this board, wiring width and wiring pitch (L/S) can be madesmall by controlling the diameter of each via hole to at most 200 μm,preferably at most 100 μm, more preferably at most 80 μm, mostpreferably at most 50 μm, thereby mounting semiconductor chips at a highdensity. In addition, mounting by a bare chip mounting method, i.e., amethod of directly connecting electrodes of semiconductor chips to asubstrate by gold wires (wire bonding; W.B), or by a method oflaminating a chip and a substrate on each other with a solder orconductive adhesive through bumps (flip chip bonding; F.C) is feasible.

[0150] The thickness of the interlayer insulating film is generally 5 to200 μm, preferably 10 to 100 μm, more preferably 20 to 80 μm, mostpreferably 30 to 50 μM. If the thickness of the insulating film is toothin, a problem arises as to insulation reliability such as migrationresistance, and the evenness of the film is lowered. If the thickness ofthe insulating film is too great, it is difficult to form minute viaholes.

[0151] (3) Performance of Board:

[0152] Heat Resistance:

[0153] In the high-density assembly board according to the presentinvention, LSI chips are mounted by bare chip mounting for the purposeof shortening a wire connecting distance between semiconductor parts anda substrate to promote the speeding up. Mounting methods include wirebonding, flip chip bonding, etc. In the case of the wire bonding,ultrasonic bonding is applied. In the case of the flip chip bonding,high-temperature solder bonding is applied. At this time, the surfacetemperature of the substrate is raised to 200° C. or higher.Accordingly, when the mechanical strength of an insulating layer at themounting temperature is greatly lowered, the yield of the bonding isgreatly lowered. If a difference between the mounting temperature andthe glass transition temperature of a material exceeds 30 to 40° C., theyield greatly increases. Therefore, it is desirable that the glasstransition temperature of an interlayer insulating film used in theboard be at least 100° C.

[0154] Dielectric Properties:

[0155] Since the high-density assembly board according to the presentinvention is particularly used for the purpose of enhancing theprocessing speed of a computer to achieve speeding up., a centralprocessing unit (CPU) of high clock frequency is mounted. Accordingly, apackaging substrate to be used is also required to have a low dielectricconstant so as to sufficiently derive the performance of CPU. Since awavelength in a high-frequency region is particularly used incommunication apparatus, the packaging substrate is required to have alow dielectric loss tangent so as to lessen transmission loss in thehigh-frequency region. Accordingly, an insulating material forming aninterlayer insulating film is also required to have a low dielectricconstant and a low dielectric loss tangent. The insulating materialaccording to the present invention has a dielectric constant of at most4.0 preferably at most 3.0 and a dielectric loss tangent of at most0.01, preferably at most 0.001 as measured at a frequency of 1 MHz.

[0156] Water Absorption Property:

[0157] A phenomenon (ion migration) that a metal of a wiring layer isionized to migrate into an insulating layer is greatly accelerated bywater in the insulating layer, resulting in dielectric breakdown. Whenthe water absorptivity of an insulating material is low, the migrationresistance of the insulating layer is improved to a great extent, and sothe insulation reliability of the board is enhanced to a great extent.The board is also required to have a lower water absorptivity as awhole. According to the present invention, a board having a waterabsorptivity of at most 0.5%, preferably 0.05% is preferably provided.

[0158] (4) Constitution of High-Density Assembly Board:

[0159] No particular limitation is imposed on the constitution of thehigh-density assembly board. However, principal examples thereof includethat having a high-density wiring layer built up on at least one side ofa substrate and a core substrate having a function as a radiator plateand that obtained by laminating a number of sheets impregnated with ainsulating material. Specific typical examples thereof include a SLCboard (IBM JAPAN, LIMITED) and an ALIVH multi-layer printed wiring board(Matsushita Electric Industrial Co., Ltd.) described in “Kiyoshi Takagi:“Trend of MCM Assembly Boards in Recent Years”, Journal of CircuitAssembly Society, Vol. 11, No. 5, 1996”.

[0160] As the core substrate, is used a metal plate, ceramic substrate,silicon wafer substrate, printed wiring substrate or the like. A wiringpattern may also be formed on the core substrate.

[0161] (5) Production of High-Density Assembly Board:

[0162] Processes for producing a high-density assembly board include{circle over (1)} a process in which an interlayer insulating layer anda metal wiring layer are formed on a core substrate, and {circle over(2)} a process in which a plurality of sheets comprising a reinforcingbase material are stacked on one another and hot-pressed.

[0163] {circle over (1)} Process of Forming Interlayer Insulating Filmon Core Substrate:

[0164] The process for forming the interlayer insulating film on thecore substrate include (a) a build-up (sequential lamination) method inwhich the above-described insulating material is laminated by a solutioncoating method such as spin coating or curtain coating, and (b) alaminating method of laminating a plurality of processed sheets on afilm to heat and press the resulting laminate.

[0165] (a) Build-Up (sequential Lamination) Method:

[0166] The interlayer insulating film is formed in accordance with thefollowing process. Namely, the above-described insulating material isapplied by a spin coating or curtain coating (casting) method on to thecore substrate and prebaked at about 90 to 100° C. for about 60 secondsto 10 minutes to form a first interlayer insulating film having a filmthickness of 3 to 100 μm.

[0167] The formation of via holes in the insulating film is conducted inthe following manner. When the insulating material is of a thermosettingtype, the insulating film is completely cured, and via holes 5 to 150 μmin diameter are then formed by an excimer laser, CO₂ laser, UV-YAG laseror the like. When the insulating material is of a photo-setting type,the insulating film is exposed to, for example, ultraviolet light havinga wavelength of 365 nm under exposure conditions of about 150 mJ/cm²using a photomask, developed with an organic solvent such as toluene toform via holes 5 to 150 μm in diameter (photolithographic method), andthen completely cured.

[0168] The formation of the metal conductor layer is conducted byforming a metal conductor pattern having a conductor width and conductorspacing of 20 to 100 μm, respectively on the insulating film, in whichthe via holes have been formed.

[0169] An interlayer insulating layer comprising 1 to 20 insulatingfilms can be formed by repeating the above-described processes.

[0170] (b) Sheet Laminating Method:

[0171] In the case of the sheet laminating method, an interlayerinsulating film is formed in the following manner. The insulatingmaterial is formed into a semi-cured sheet 3 to 100 μm thick in advanceby a cast film process.

[0172] The sheet is bonded to the above-described core substrate whilecuring the sheet by hot-pressing using a press or the like. After this,a metal conductor layer is formed in the same manner as in the build-upmethod except that the formation of interlayer-connecting via holes isconducted by a laser. A second interlayer insulating film is then formedin the same manner as described above. An interlayer insulating layercomprising 1 to 20 insulating films can be formed by repeating theabove-described processes.

[0173] {circle over (2)} Process of Forming Interlayer Insulating Filmby Sheets Comprising Reinforcing Base Material:

[0174] In the case where the interlayer insulating film is formed bysheets comprising a reinforcing base material, the above-describedinsulating material is impregnated into a reinforcing base materialcapable of forming via holes by a laser, and a solution is dried toremove, thereby forming a sheet (prepreg). A plurality of such sheetsare stacked on one another while forming a metal conductor pattern inthe same manner as in the sheet laminating method, and hot-pressed intoa laminate.

[0175] In order to form a higher-density multi-layer wiring layer, it ispreferred to form the interlayer insulating layer by the build-up methodcapable of forming minute via holes among the above various processesand methods.

[0176] When the cycloolefin polymer has a high glass transitiontemperature, the above respective interlayer insulating films may beformed without particular curing.

[0177] (6) Semiconductor Package:

[0178] In the present invention, a semiconductor package can befabricated in accordance with any publicly known process except that theabove high-density assembly board is used. For example, semiconductorparts such as LSI chips are mounted on at least one side of thehigh-density assembly board by the above-described mounting method, andin particular, a connected part between electrodes of the semiconductorparts and electrodes of the high-density assembly board is sealed with asealing material such as an epoxy resin. A plurality of electrodes arethen arranged by metal wiring on an area of one side (a side on whichthe number of parts mounted is fewer) of the board on which thesemiconductor parts have been mounted, and connecting members, forexample, solder balls or the like are provided.

[0179] The integral part comprising the semiconductor parts,high-density assembly board and connecting members produced by theabove-described process is referred to as a semiconductor package. Inparticular, packages in which at least two semiconductor parts aremounted are useful in using as multi chip modules (MCM) in computers andcommunication apparatus. These packages and modules are furtherconnected to a mother board (ordinary printed wiring board) through theabove-described connecting members, or may be used as mother board asthey are.

[0180] When the connecting members are solder balls, they are mounted asa ball grid array (BGA) on computers and communication apparatus.

[0181] [Dry Film]

[0182] (1) Form of Dry Film:

[0183] The dry film is provided in a state that the curable cycloolefinpolymer composition (curable resin composition) has been formed into afilm by a casting process or the like, and a solvent has been completelyremoved from the film.

[0184] The hardener is uniformly dispersed or dissolved in the curableresin composition. Although the film may be either not cured at all orsemi-cured, it is preferred that the film be not cured at all from theviewpoint of improvement in viscosity characteristics in order to heat,melt and press-bond it upon lamination.

[0185] No particular limitation is imposed on the thickness of the dryfilm. However, it is generally 10 to 200 μm, preferably 20 to 100 μm,more preferably 30 to 80 μm. Any thickness too small is not preferredbecause the insulation reliability of the film is lowered, anddifficulties are encountered on its smoothing and build-up laminating.Any thickness too great is also not preferred because there are causedsuch problems that it is hard to form minute via holes, and residualstress tends to remain. The thickness of the film within the above rangeis preferred because these properties are balanced with each other at ahigh level.

[0186] No particular limitation is imposed on the process for formingthe dry film. However, examples thereof include a process (castingprocess) in which a varnish comprising the polymer and various othercomponents dissolved or dispersed in a solvent is applied on to a flatsubstrate and dried, and the like. Examples of the solvent used includearomatic solvents such as benzene, toluene, o-, m- and p-xylene,ethylbenzene, propylbenzene, cumene, butylbenzene, t-butylbenzene, ando-, m- and p-benzonitrile; hydrocarbon solvents such as cyclohexane anddecahydronaphthalenen; halogenated solvents such as methylene chloride,chloroform, carbon tetrachloride, ethylene dichloride, chlorobenzene,o-, m- and p-dichlorobenzene, and trichlorobenzene; ether solvents suchas tetrahydrofuran (THF), tetrahydropyran, anisole and dimethoxyethane;ketone solvents such as methyl ethyl ketone (MEK), methyl isobutylketone (MIBK) and cyclohexanone; and ester solvents such as ethylacetate, butyl acetate, phenyl acetate and phenyl benzoate. Thesesolvent may be used in combination for the purpose of, for example,controlling drying rate. The resin may also be partially cured in adrying step to control the flowability of the resin in a laminatingstep.

[0187] (2) Multi-Layer Laminate:

[0188] The conventionally known process for producing a multi-layerlaminate may be applied as a process for producing a laminated boardusing the dry film according to the present invention as it is. Theprocess will hereinafter be described.

[0189] Substrate:

[0190] The dry film is first laminated on a substrate (core substrate)serving as a core. No particular limitation is imposed on the substrate.Examples thereof include a double-sided copper-clad laminate substrate,a one-sided copper-clad laminate substrate, a metal substrate, a ceramicsubstrate and a silicon wafer substrate. A circuit pattern may also beformed in advance on these core substrates.

[0191] As a process for forming the pattern on the substrate, there maybe used, for example, a process in which the surface of the ceramic orsilicon wafer substrate is subjected to sputter cleaning, a film ofaluminum in a thickness of up to about 4 μm is formed on at least oneside of the substrate by a sputtering method, a film of chromium in athickness of about 0.15 μm is successively formed thereon to form apassivation film, and chromium and aluminum are then selectively etchedto form a first metal wiring. When the core substrate is more generallyused, an ordinary glass-epoxy copper-clad laminate substrate is used asa base, and a first wiring layer is also formed in the form of copperwiring having a thickness of ten odd pin on a glass-epoxy copper-cladwiring plate in order of electroless plating and electroplating.

[0192] Production of Laminate:

[0193] The dry film according to the present invention is laminated onat least one side of the core substrate, whereby a laminate can beproduced. The laminating is generally conducted by hot pressing or pressbonding under reduced pressure. However, an adhesive may also be used.In the case where particularly high density is required, the thicknessof the dry film also thins. Therefore, the press bonding under reducedpressure is preferred to the hot pressing because mixing of bubbles,occurrence of lamination mark, etc. can be prevented. In the case of thepress bonding under reduced pressure, a vacuum laminator or the like maypreferably be used.

[0194] Production Process of Multi-Layer Laminate:

[0195] {circle over (1)} Build-Up of Dry Film on the Laminate:

[0196] The dry film laminated is subjected to curing and formation ofinterlayer-connecting via holes in the following manner, thereby forminga wiring circuit pattern on the surface, and moreover individual wiringlayers are electrically connected to each other in accordance with thefollowing process. After an additional dry film is laminated thereon, awiring pattern is formed in the same manner as described above. Amulti-layer laminate is produced by repeating these processes at leastonce.

[0197] {circle over (2)} Curing of the Resin and Formation ofInterlayer-Connecting via Holes:

[0198] The curable resin composition laminated on the substrate is curedfor the purpose of enhancing the heat resistance and reducing thecoefficient of linear expansion. The curing of the resin may beconducted either by photo-setting or by heat curing.

[0199] (a) Case of Curing by Light:

[0200] In the case of curing by light, a mask film is brought into closecontact under reduced pressure with the laminate to conduct exposurewith ultraviolet light or the like. Exposure conditions are suitablypreset according to the properties of the resin and the thickness of thefilm. After the exposure, development is conducted with a developersuitably selected to form the interlayer-connecting via holes. After theformation of the via holes, it is preferable to conduct curing byultraviolet light or heat so as to more completely cure the resin.

[0201] (b) Case of Curing by Heat:

[0202] In the case of a thermosetting (non-photosensitive) dry film, thefilm is brought into close contact with the laminate and then completelycured by heating. Thereafter, interlayer-connecting via holes are formedby a laser beam. The formation of the via holes by the laser beam isconducted by scanning a laser to chemically decompose the resin.Examples of the laser include excimer laser, carbon dioxide laser,UV-YAG laser, etc. The carbon dioxide laser is principally used.

[0203] {circle over (3)} Formation of Conductive Layer (Wiring CircuitPattern):

[0204] As a process for forming a wiring patter, the conventionallyknown process for forming a wiring pattern on a printed wiring board canbe utilized as it is. In general, chemical plating is applied after theformation of the interlayer-connecting via holes. Specifically, after aplating resist is applied, patterning is conducted to form a conductivelayer for wiring circuit by a means such as plating (in order ofelectroless plating and electroplating) or sputtering. At the same timeas the formation of the wiring pattern by chemical plating, chemicalplating is also applied to wall surfaces of the interlayer-connectingvia holes to electrically connect the individual wiring layer to eachother.

[0205] {circle over (4)} Laminating Process of Dry Film:

[0206] No particular limitation is imposed on the process for buildingup a dry film on the core substrate or the laminate on which another dryfilm has been laminated. However, examples thereof include hot-rolllamination, hot pressing and vacuum lamination as described above.

[0207] Uses:

[0208] The build-up multi-layer laminates thus formed are useful, inparticular, as high-density assembly boards and semiconductor packageboards in fields of information processing such as computers, andinformation communication of which assembly boards excellent inreliability, heat resistance, dielectric properties, etc. are required.

[0209] [Resin-Attached Metal Foil]

[0210] (1) Metal Foil:

[0211] Any metal foil may be used as a metal foil used in the presentinvention so far as it can be used as a conductive layer. However,examples thereof include copper foil, aluminum foil, tin foil and goldfoil. The copper foil and aluminum foil are preferred from the viewpointof easy availability and etching, with the copper foil beingparticularly preferred. The thickness of the metal foil used isgenerally 1 to 500 μm, preferably 2 to 200 μm, more preferably 5 to 150μm.

[0212] If the thickness of the metal foil is too thin, there is caused aproblem that the metal foil is cracked due to a difference incoefficient of linear expansion between a resin layer and the metalfoil. If the thickness is too great, it is difficult to form a minutewiring. Of the surfaces of the metal foil, a surface on which a resinlayer will be formed may also be subjected to a surface rougheningtreatment with a chemical or physical treatment, or a coupling treatmentfor the purpose of enhancing its adhesion property to the resin. Asurface roughened electrolytic copper foil sold for production ofcopper-clad printed wiring board may be used for the resin-attachedcopper foil according to the present invention as it is.

[0213] (2) Build-Up Multi-Layer Laminate:

[0214] The conventionally known process for producing a build-uplaminate board may be applied as a process for producing a build-upmulti-layer board using the resin-attached metal foil according to thepresent invention as it is. The process will hereinafter be described.

[0215] Substrate:

[0216] The resin-attached metal foil is first laminated on a substrate(core substrate) serving as a core. No particular limitation is imposedon the substrate. Examples thereof include a double-sided copper-cladlaminate substrate, a one-sided copper-clad laminate substrate, a metalsubstrate, a ceramic substrate and a silicon wafer substrate. A circuitpattern may also be formed in advance on these core substrates.

[0217] As a process for forming the pattern on the substrate, there maybe used, for example, a process in which the surface of the ceramic orsilicon wafer substrate is subjected to sputter cleaning, a film ofaluminum in a thickness of up to about 4 μm is formed on at least oneside of the substrate by a sputtering method, a film of chromium in athickness of about 0.15 μm is successively formed thereon to form apassivation film, and chromium and aluminum are then selectively etchedto form a first metal wiring. When the core substrate is more generallyused, an ordinary glass-epoxy copper-clad laminate substrate is used asa base, and a first wiring layer is also formed in the form of copperwiring having a thickness of ten-odd μm on a glass-epoxy copper-cladwiring plate in order of electroless plating and electroplating.

[0218] Production of Laminate:

[0219] The resin-attached metal foil according to the present inventionis laminated on at least one side of the core substrate with the side ofthe resin film turned inside, whereby a laminate can be produced. Thelaminating is generally conducted by hot pressing. However, an adhesivemay also be used.

[0220] Production Process of Build-Up Multi-Layer Laminate:

[0221] {circle over (1)} Build-Up of Dry Film on the Laminate:

[0222] The resin-attached metal foil laminated is then treated in thefollowing manner. At least part of the metal foil is removed to form awiring circuit pattern on the metal foil side, and individual wiringlayers are electrically connected to each other in accordance with thefollowing process. After an additional resin-attached metal foil islaminated thereon with the side of the resin film turned inside, awiring pattern is formed in the same manner as described above. Abuild-up multi-layer laminated board is produced by repeating theseprocesses at least once.

[0223] {circle over (2)} Curing of the Resin:

[0224] The cycloolefin polymer (resin) formed on the metal foil ispreferably cured by heat by blending a hardener for the purpose ofenhancing the heat resistance and reducing the coefficient of linearexpansion.

[0225] The heat curing of the cycloolefin polymer may be conductedeither at the same time as bonding by heating and pressing or byseparate heating after the bonding by heating and pressing. The curingof the polymer may be conducted either upon the build-up laminating orby collectively heating polymer layers after completion of alllaminating steps without completely curing it upon the build-uplaminating. However, it is preferred to completely cure the polymer uponeach build-up laminating in order to enhance the chemical resistance inthe formation of a circuit pattern and an etching treatment upon a smearremoving treatment.

[0226] {circle over (3)} Formation of Wiring Circuit Pattern:

[0227] Examples of a process for forming a wiring pattern on theresin-attached metal foil according to the present invention include thefollowing two processes. According to the first process, theresin-attached metal foil is bonded by heating and pressing to the coresubstrate to cure the resin, and an etching resist is then applied tothe metal foil to pattern it. Thereafter, unnecessary parts of the metalfoil is removed by an etchant. The wiring circuit pattern formed afterseparating the etching resist remaining on the wiring pattern is used asa conductor layer as it is, or chemical plating is applied after theformation of interlayer-connecting via holes. According to the secondprocess, after the resin-attached metal foil is similarly bonded byheating and pressing to the core substrate to cure the resin, and thewhole metal foil is separated by an etchant, a plating resist isapplied, and patterning is then conducted to form a conductive layer forwiring circuit by a means such as plating (in order of electrolessplating and electroplating) or sputtering.

[0228] {circle over (4)} Laminating Process of Resin-Attached MetalFoil:

[0229] No particular limitation is imposed on the process for bonding aresin-attached metal foil by heating and pressing on the core substrateor the build-up multi-layer laminate to which another resin-attachedmetal foil has been bonded by heating and pressing. However, examplesthereof include hot-roll lamination and hot pressing.

[0230] Uses:

[0231] The build-up multi-layer laminates thus formed are useful, inparticular, as high-density assembly boards and semiconductor packageboards in fields of information processing such as computers, andinformation communication of which assembly boards excellent inreliability, heat resistance, dielectric properties, etc. are required.

EXAMPLES

[0232] The present invention will hereinafter be described morespecifically by the following Preparation Examples, Examples andComparative Examples. All designations of “part” or “parts” and “%” aswill be used in these examples mean part or parts by weight and wt. %unless expressly noted.

[0233] Various physical properties were determined in accordance withthe following methods:

[0234] (1) The glass transition temperature was measured in accordancewith the differential scanning calorimetry (DSC method).

[0235] (2) The molecular weight was determined in terms of polystyreneas measured by gel permeation chromatography (GPC) using toluene as asolvent unless expressly noted.

[0236] (3) The copolymerization ratio was determined by ¹H—NMR.

[0237] (4) The epoxy group content was determined by ¹H—NMR, andcalculated out in accordance with the above-described equation 1.

[0238] (5) The carboxyl group content was determined by ¹H—NMR, andcalculated out in accordance with the above-described equation 1.

[0239] (6) The hydroxyl group content was determined by ¹H—NMR, andcalculated out in accordance with the above-described equation 1.

[0240] (7) The adhesion property to a metal was determined in terms ofthe 1-cm wide peel strength of a copper plated layer 18 μm thick inaccordance with JIS C 6481.

[0241] (8) The moisture resistance was evaluated by leaving a testsample to stand for 1,000 hours under conditions of 85° C. and 85%relative humidity and then applying voltage of 1 kV between layers todetermine percent defective.

[0242] (9) The heat resistance was evaluated by determining yield uponwire-bonding an LSI chip on a build-up board. Any board insufficient inheat resistance is deformed by heat upon the wire bonding, therebylowing connection yield.

[0243] (10) The dielectric constant and dielectric loss tangent weredetermined at 1 MHz in accordance with JIS K 6911.

[0244] (11) The water absorptivity was determined by using a disk-likespecimen 50 mm in diameter and 3 mm in thickness produced by a castingprocess in accordance with JIS K 7209.

Preparation Example 1 (Preparation of Epoxy-Modified NorborneneCopolymer)

[0245] <Polymerization>

[0246] An addition copolymer of 2-norbornene (NB) and5-decyl-2-norbornene (DNB) [number average molecular weight (Mn)=69,200,weight average molecular weight (Mw)=132,100, both, in terms ofpolystyrene; compositional ratio (NB/DNB) of monomers=76/24 (molarratio); Tg=260° C.] was obtained in accordance with the publicly knownprocess described in U.S. Pat. No. 5,468,819.

[0247] <Epoxy Modification>

[0248] Dissolved in 130 parts of t-butylbenzene were 28 parts of thethus-obtained norbornene copolymer, 10 parts of 5,6-epoxy-1-hexene and 2parts of dicumyl peroxide, and a reaction was conducted at 140° C. for 6hours. A solution of the resultant reaction product was poured into 300parts of methanol to solidify the reaction product. The epoxy-modifiedpolymer thus solidified was dried under reduced pressure at 100° C. for20 hours, thereby obtaining 26 parts of an epoxy-modified norbornenecopolymer. This resin had Mn of 72,600, Mw of 198,400 and Tg of 265° C.The epoxy group content in the epoxy-modified norbornene copolymer was2.4% per repeating structural unit of the polymer as measured by ¹H—NMR.When 15 parts of this epoxy-modified norbornene copolymer and 0.6 partsof 4,4′-bisazidobenzal(4-methyl)cyclohexane as a photoreactive substancewere dissolved in 45 parts of xylene, a uniform solution was providedwithout forming any precipitate.

Preparation Example 2 (Preparation of Epoxy-Modified Norbornene/EthyleneCopolymer)

[0249] <Polymerization>

[0250] An addition copolymer of NB and ethylene [Mn=66,200, Mw=142,400;compositional ratio (NB/ethylene) of monomers=63/37 (molar ratio);Tg=184° C.] was obtained in accordance with the publicly known processdescribed in Japanese Patent Application Laid-Open No. 292020/1995.

[0251] <Epoxy Modification>

[0252] Dissolved in 130 parts of t-butylbenzene were 30 parts of thethus-obtained norbornene/ethylene copolymer, 10 parts of5,6-epoxy-1-hexene and 2 parts of dicumyl peroxide, and a reaction wasconducted at 140° C. for 6 hours. A solution of the resultant reactionproduct was poured into 300 parts of methanol to solidify the reactionproduct. The epoxy-modified polymer thus solidified was dried underreduced pressure at 100° C. for 20 hours, thereby obtaining 29 parts ofan epoxy-modified norbornene/ethylene copolymer. This resin had Mn of82,400, Mw of 192,300 and Tg of 185° C. The epoxy group content in theepoxy-modified norbornene copolymer was 2.4% per repeating structuralunit of the polymer as measured by ¹H—NMR. When 15 parts of thisepoxy-modified norbornene copolymer and 0.6 parts of4,4′-bisazidobenzal(4-methyl)cyclohexane as a photoreactive substancewere dissolved in 45 parts of xylene, a uniform solution was providedwithout forming any precipitate.

Preparation Example 3 (Preparation of Epoxy-Modified NorborneneTerpolymer)

[0253] <Polymerization>

[0254] Polymerization was conducted in the same manner as in PreparationExample 1 except that 18 parts of 5-hexyl-2-norbornene (HNB) was used inplace of 26 parts of 5-decyl-2-norbornene, and 3 parts of5-ethylidene-2-norbornene (ENB) were added, thereby obtaining 21 partsof a norbornene terpolymer [Mn=71,100, Mw=107,000; compositional ratioNB/HNB/ENB of monomers=74/23/3 (molar ratio); Tg=323° C.] was obtained.

[0255] <Epoxy Modification>

[0256] Thirty parts of the thus-obtained norbornene terpolymer wereadded to 120 parts of toluene and heated to 120° C. into a solution. Tothe solution were added 1.2 parts of t-butyl hydroperoxide and 0.09parts of hexacarbonylmolybdenum, and the mixture was refluxed for 2hours. The reaction mixture was poured into 100 parts of cold methanolto solidify a reaction product. The epoxy-modified polymer thussolidified was dried under reduced pressure at 80° C. for 20 hours,thereby obtaining 30 parts of an epoxy-modified norbornene terpolymer.This epoxy-modified norbornene terpolymer had Mn of 85,200, Mw of154,600 and Tg of 328° C. The epoxy-modified rate to the unsaturatedbonds was 100% as measured by ¹H—NMR, and the epoxy group content was3.0% per repeating structural unit of the polymer. When 15 parts of thisepoxy-modified norbornene copolymer and 0.6 parts of4,4′-bisazido-benzal(4-methyl)cyclohexane as a photoreactive substancewere dissolved in 45 parts of xylene, a uniform solution was providedwithout forming any precipitate.

Preparation Example 4 (Maleic Acid-Modified Norbornene Copolymer)

[0257] <Maleic Acid Modification>

[0258] Thirty parts of the norbornene copolymer obtained in PreparationExample 1 were added to 150 parts of toluene and heated to 120° C. intoa solution. To the solution were gradually added a solution of maleicanhydride (3 parts) in toluene (100 parts) and a solution of dicumylperoxide (0.3 parts) in toluene (45 parts), thereby conducting areaction for 4 hours. The reaction mixture was poured into 600 parts ofcold methanol to solidify a reaction product. The modified polymer thussolidified was dried under reduced pressure at 80° C. for 20 hours,thereby obtaining 30 parts of a maleic acid-modified norbornenecopolymer. This resin had Mn of 73,100, Mw of 162,400 and Tg of 266° C.The maleic acid content in the modified polymer was 2.5% per repeatingstructural unit of the polymer as measured by ¹H—NMR. When 15 parts ofthis maleic acid-modified norbornene copolymer, 9 parts of triallylcyanurate as a crosslinking aid and 1.2 parts of2,5-dimethyl-2,5-di(t-butyl peroxy)-hexyne-3 as a peroxide weredissolved in 45 parts of xylene, a uniform solution was provided withoutforming any precipitate.

Preparation Example 5 (Hydroxy-Modified NB/HNB/ENB Terpolymer)

[0259] <Hydroxy Modification>

[0260] Thirty parts of the norbornene terpolymer obtained in PreparationExample 3 were added to 300 parts of toluene and heated to 120° C. intoa solution. To the solution were gradually added dropwise 50 parts of90% formic acid and 7.5 parts of 30% aqueous hydrogen peroxide, followedby refluxing for 2 hours. The reaction mixture was then neutralized witha methanol solution of sodium hydroxide and poured into 700 parts ofacetone to solidify a reaction product. The modified polymer thussolidified was dried under reduced pressure at 80° C. for 20 hours,thereby obtaining 30 parts of a hydroxy-modified norbornene terpolymer.This hydroxy-modified norbornene terpolymer had Mn of 82,100, Mw of133,400 and Tg of 328° C. The hydroxy-modified rate to the unsaturatedbonds was 100% as measured by ¹H—NMR, and the hydroxy content was 3.0%per repeating structural unit of the polymer. When 15 parts of thishydroxy-modified norbornene terpolymer, 9 parts of triallyl cyanurateand 1.2 parts of 2,5-dimethyl-2,5-di(t-butyl peroxy)hexyne-3 weredissolved in 45 parts of xylene, a uniform solution was provided withoutforming any precipitate.

Preparation Example 6

[0261] <Polymerization>

[0262] Ring-opening polymerization and hydrogenation reaction ofmethylmethoxytetracyclododecene were conducted in accordance with thepublicly known process described in Japanese Patent ApplicationLaid-Open No. 77520/1992 to obtain a hydrogenated product of aring-opening polymer having a rate of hydrogenation of 100%, a numberaverage molecular weight (Mn) of 16,400 in terms of polystyrene, aweight average molecular weight (Mw) of 58,100 and Tg of 172° C.

[0263] When 15 parts of the hydrogenated product of the ring-openingpolymer thus obtained, 9 parts of triallyl cyanurate as a crosslinkingaid and 1.2 parts of 2,5-dimethyl-2,5-di(t-butyl peroxy)hexyne-3 weredissolved in 45 parts of xylene, a uniform solution was provided withoutforming any precipitate.

Preparation Example 7

[0264] <Polymerization>

[0265] Addition polymerization and hydrogenation reaction ofcyclohexadiene were conducted in accordance with the publicly knownprocess described in Japanese Patent Application Laid-Open No.258318/1995 to obtain a polymer having a number average molecular weight(Mn) of 48,300 in terms of polystyrene, a weight average molecularweight (Mw) of 72,200 and Tg of 218° C. The rate of hydrogenation of theresultant hydrogenated product of the cyclic conjugated diene polymerwas 85% as determined by ¹H—NMR.

[0266] <Epoxy Modification>

[0267] Thirty parts of the thus-obtained hydrogenated product of thecyclic conjugated diene polymer were added to 120 parts of toluene andheated to 120° C. into a solution. To the solution were added 1.2 partsof t-butyl hydroperoxide and 0.09 parts of hexacarbonylmolybdenum, andthe mixture was refluxed for 2 hours. The reaction mixture was pouredinto 300 parts of cold methanol to solidify a reaction product. Theepoxy-modified polymer thus solidified was dried under reduced pressureat 80° C. for 20 hours, thereby obtaining 30 parts of an epoxy-modifiedhydrogenated product of the cyclic conjugated diene polymer. Thishydrogenated product of the cyclic conjugated diene polymer had Mn of68,200, Mw of 122,100 and Tg of 220° C. The epoxy-modified rate to theunsaturated bonds was 100% as measured by ¹H—NMR, and the epoxy groupcontent was 15% per repeating structural unit of the polymer. When 15parts of the hydrogenated product of the cyclic conjugated diene polymerand 0.6 parts of 4,4′-bisazidobenzal(4-methyl)cyclohexane as aphotoreactive substance were dissolved in 45 parts of xylene, a uniformsolution was provided without forming any precipitate.

Preparation Example 8 (Hydrogenated Product of Ring-Opening Polymer)

[0268] <Polymerization>

[0269] Ring-opening polymerization and hydrogenation oftetracyclododecene and 8-methyltetracyclododecene were conducted inaccordance with the publicly known process described in Japanese PatentApplication Laid-Open No. 363312/1992 to obtain a hydrogenated productof a ring-opening copolymer having a number average molecular weight(Mn) of 31,200 in terms of polystyrene, a weight average molecularweight (Mw) of 55,800 and Tg of 158° C. The rate of hydrogenation of theresultant polymer was at least 99% as determined by ¹H—NMR.

[0270] <Epoxy Modification>

[0271] Dissolved in 130 parts of t-butylbenzene were 28 parts of thethus-obtained hydrogenated product of the ring-opening copolymer, 10parts of 5,6-epoxy-1-hexene and 2 parts of dicumyl peroxide, and areaction was conducted at 140° C. for 6 hours. A solution of theresultant reaction product was poured into 300 parts of methanol tosolidify the reaction product. The epoxy-modified polymer thussolidified was dried under reduced pressure at 100° C. for 20 hours,thereby obtaining 28 parts of an epoxy-modified hydrogenated product ofthe ring-opening copolymer. This epoxy-modified hydrogenated product ofthe ring-opening copolymer had Mn of 38,600, Mw of 85,100 and Tg of 165°C. The epoxy group content in the epoxy-modified hydrogenated product ofthe ring-opening copolymer was 2.0% per repeating structural unit of thepolymer as measured by ¹H—NMR. When 15 parts of the epoxy-modifiedhydrogenated product of the ring-opening copolymer and 0.6 parts of4,4′-bisazidobenzal(4-methyl)cyclohexane as a photoreactive substancewere dissolved in 45 parts of xylene, a uniform solution was providedwithout forming any precipitate.

Preparation Example 9

[0272] Addition polymerization of TCD and ethylene was conducted inaccordance with the publicly known process described in Japanese PatentApplication Laid-Open No. 173112/1990 to obtain an addition polymer[Mn=46,200, Mw=87,500; compositional ratio (TCD/ethylene) ofmonomers=40/60 (mol %); Tg=143° C.].

[0273] Dissolved in 120 parts of cyclohexane were 50 parts of thethus-obtained polymer, 6 parts of 5,6-epoxy-1-hexene and 1.5 parts byweight of dicumyl peroxide, and a reaction was conducted at 150° C. for1.5 hours in an autoclave. A solution of the resultant reaction productwas poured into 240 parts of isopropyl alcohol to solidify the reactionproduct. The reaction product thus solidified was then dried underreduced pressure at 100° C. for 20 hours to obtain 50 parts by weight ofan epoxy group-containing norbornene copolymer. This epoxygroup-containing norbornene copolymer had Mn of 55,400, Mw of 100,600and Tg of 148° C. The epoxy group content in the epoxy group-containingnorbornene copolymer was 1.2% per repeating structural unit of thepolymer as measured by ¹H—NMR.

[0274] When 15 parts of the thus-obtained epoxy group-containingnorbornene copolymer and 0.6 parts of4,4′-bisazidobenzal(4-methyl)cyclohexane as a photoreactive substancewere dissolved in 45 parts of xylene, a uniform solution was providedwithout forming any precipitate.

[0275] The monomer constitution, molecular weight, polar group and rateof modification of each of the resins obtained in Preparation Examples 1to 9 are shown in Table 1. TABLE 1 Comp. ratio Rate of of monomersmodifi- Base (molar Tg Polar cation Tg polymer(*1) ratio) Mn Mw (° C.)group (mol %) Mn Mw (° C.) Prep. NB/DNB 76/24 69,200 132,100 260 Epoxy2.4 72,600 198,400 265 Ex. 1 Prep. NB/Ethylene 63/37 66,200 142,400 184Epoxy 2.4 82,400 192,300 185 Ex. 2 Prep. NB/HNB/ENB 74/23/3 71,100107,000 323 Epoxy 3.0 85,200 154,600 328 Ex. 3 Prep. NB/DNB 76/24 69,200132,100 260 Carboxyl 2.5 73,100 162,400 266 Ex. 4 Prep. NB/HNB/ENB74/23/3 71,100 107,000 323 Hydroxyl 3.0 82,100 133,400 328 Ex. 5 Prep.Methoxymethyl- 100 18,500 48,700 — Carbonyl 100.0 19,400 58,100 172 Ex.6 TCD Prep. Cyclohexadiene 100 48,300 72,200 218 Epoxy 15.0 68,200122,100 220 Ex. 7 Prep. TCD/MethylTCD 46/54 31,200 55,800 158 Epoxy 2.038,600 85,100 165 Ex. 8 Prep. TCD/Ethylene 40/60 46,200 87,500 143 Epoxy1.2 55,400 100,600 148 Ex. 9

Example 1

[0276] <Formation of Interlayer Insulating Film>

[0277] The uniform solution obtained in Preparation Example 1 wasfiltered through a precision filter made of polytetrafluoroethylene(PTFE) having a pore size of 0.22 μm to obtain a curable polymercomposition. The solution thus obtained was coated on a glass-epoxy4-layer substrate by means of a spinner, and then prebaked at 80° C. for90 seconds to form a coating film (insulating layer) having a filmthickness of 40 μm. The coating film was exposed to ultraviolet lighthaving light intensity of 150 mJ/cm² at 365 nm using a test pattern maskfor formation of via holes and then developed with cyclohexane to formvia holes 50 μm in diameter. The thus-treated coating film was thencured by heating at 220° C. for 4 hours under nitrogen in an oven. Afterthe whole surface of the coating film was then plated with copper toform a copper layer 15 μm thick, a resist was applied thereto, exposedusing a mask for wiring pattern and then developed. The thus-treatedcopper layer was etched by immersing the substrate in an aqueoussolution of ammonium persulfate, and the resist was separated to obtaina laminate in which copper wiring had been formed. The above steps,i.e., {circle over (1)} the coating of the interlayer insulating layer,{circle over (2)} the formation of the via holes, and {circle over (3)}the formation of the copper wiring layer, were repeated to obtain a3-layer laminated wiring circuit board. With respect to the laminatethus obtained, the via hole-forming ability, dielectric properties,water absorptivity, heat resistance, adhesion property to copper wiringand moisture resistance were determined. The results are shown in Table2.

Example 2

[0278] A 3-layer laminated wiring circuit board was formed in the samemanner as in Example 1 except that the uniform solution obtained inPreparation Example 2 was used, and was evaluated. The results are shownin Table 2.

Example 3

[0279] A 3-layer laminated wiring circuit board was formed in the samemanner as in Example 1 except that the uniform solution obtained inPreparation Example 3 was used, and was evaluated. The results are shownin Table 2.

Example 4

[0280] The uniform solution obtained in Preparation Example 4 wasfiltered through a precision filter made of PTFE having a pore size of0.22 μm to obtain a curable polymer composition. The solution thusobtained was coated on a glass-epoxy 4-layer substrate by means of aspinner, and then prebaked at 80° C. for 90 seconds to form a coatingfilm (insulating layer) having a film thickness of 40 μm. After thecoating film was further heated at 220° C. for 4 hours to completelycure it, via holes 50 μm in diameter were formed therein using a UV-YAGlaser. After the whole surface of the coating film was then plated withcopper to form a copper layer 15 μm thick, a resist was applied thereto,exposed using a mask for wiring pattern and then developed. Thethus-treated copper layer was etched by immersing the substrate in anaqueous solution of ammonium persulfate, and the resist was separated toobtain a laminate in which copper wiring had been formed. The abovesteps, i.e., {circle over (1)} the coating of the interlayer insulatinglayer, {circle over (2)} the formation of the via holes, and {circleover (3)} the formation of the copper wiring layer, were repeated toobtain a 3-layer laminated wiring circuit board. With respect to thelaminate thus obtained, the via hole-forming ability, dielectricproperties, water absorptivity, heat resistance, adhesion property tocopper wiring and moisture resistance were determined. The results areshown in Table 2.

Example 5

[0281] A 3-layer laminated wiring circuit board was formed in the samemanner as in Example 4 except that the uniform solution obtained inPreparation Example 5 was used, and a carbon dioxide laser was used inthe formation of via holes 50 μm in diameter, and was evaluated. Theresults are shown in Table 2.

Example 6

[0282] A 3-layer laminated wiring circuit board was formed in the samemanner as in Example 4 except that the uniform solution obtained inPreparation Example 6 was used, and was evaluated. The results are shownin Table 2.

Example 7

[0283] A 3-layer laminated wiring circuit board was formed in the samemanner as in Example 1 except that the uniform solution obtained inPreparation Example 7 was used, and was evaluated. The results are shownin Table 2.

Example 8

[0284] A 3-layer laminated wiring circuit board was formed in the samemanner as in Example 1 except that the uniform solution obtained inPreparation Example 8 was used, and was evaluated. The results are shownin Table 2.

Comparative Example 1 (Formation of Photosensitive Polyimide InterlayerInsulating Film)

[0285] A solution of polyamic acid, into the carboxyl group of which anester bond had been introduced, was coated on a silicon wafer by meansof a spinner, and then prebaked at 80° C. for 90 seconds to form acoating film (insulating layer) having a film thickness of 40 μm. Thecoating film was exposed to ultraviolet light of 300 mJ/cm² using a testpattern mask for formation of via holes and then developed with analkali to form via holes 50 μm in diameter. The thus-treated coatingfilm was heat-treated at 350° C. for 3 hours under nitrogen in an oven,thereby imidating it by dehydration ring-closing reaction. Thereafter,the same process as in Example 1 was followed to obtain a laminate. Withrespect to the laminate thus obtained, the via hole-forming ability,dielectric properties, water absorptivity, heat resistance, adhesionproperty to copper wiring and moisture resistance were determined. Theresults are shown in Table 2.

Comparative Example 2 (Photosensitive Epoxy Resin Insulating Varnish)

[0286] An insulating varnish for formation of photo-via holescomprising, as a main component, a bisphenol type epoxy resin, to whichphotosensitivity had been imparted by acryl modification, was coated ona glass-epoxy 4-layer substrate by spin coating, and then prebaked at80° C. for 90 seconds to form a coating film (insulating layer) having afilm thickness of 40 μm. Thereafter, the same process as in ComparativeExample 1 except that the curing temperature was changed to 150° C. wasfollowed to obtain a laminate. With respect to the laminate thusobtained, the via hole-forming ability, dielectric properties, waterabsorptivity, heat resistance, adhesion property to copper wiring andmoisture resistance were determined. The results are shown in Table 2.

Comparative Example 3

[0287] The uniform solution obtained in Preparation Example 9 wasfiltered through a precision filter made of PTFE having a pore size of0.22 μm to obtain a curable polymer composition. A multi-layer laminatedwiring circuit board was fabricated in the same manner as in Example 1except that curing was conducted at 150° C. for 3 hours under nitrogenupon the formation of the interlayer insulating film, and was evaluated.The results are shown in Table 2. TABLE 2 Moisture Wiring resistanceWiring density Via hole Heat Water (percent Dielectric Dielectricpeeling L/S Via hole forming resistance, absorptivity defective)constant loss tangent strength (μm/μm) diameter(μm) ability W.B yield(%) (%) (%) (1 MHz) (1 MHz) (kg/cm²) Ex. 1 80/80 50 Good >90 0.05 0.02.5 0.0007 >1.0 Ex. 2 80/80 50 Good >85 0.05 0.0 2.5 0.0007 >1.0 Ex. 380/80 50 Good >90 0.06 0.0 2.6 0.0008 >1.1 Ex. 4 80/80 50 Good >90 0.050.0 2.5 0.0007 >1.0 Ex. 5 80/80 50 Good >90 0.06 0.0 2.6 0.0008 >1.1 Ex.6 80/80 50 Good >85 0.08 0.0 2.8 0.0012 >1.2 Ex. 7 80/80 50 Good >900.07 0.0 2.7 0.0010 >1.1 Ex. 8 80/80 50 Good >80 0.05 0.0 2.50.0007 >1.2 Comp. 80/80 50 (*1) >90 0.30 2.0 3.2 0.0300 >1.2 Ex. 1 Comp.80/80 50 (*2) <60 0.25 4.0 4.0 0.1500 >1.2 Ex. 2 Comp. 80/80 50 Good <500.05 0.0 2.4 0.0070 >1.0 Ex. 3

Example 9

[0288] A high-density assembly board was fabricated in the same manneras in Example 4 except that the unmodified norbornene copolymer inPreparation Example 1 was used in place of the epoxy-modified norbornenecopolymer obtained in Preparation Example 1, and triallyl cyanurate and2,5-dimethyl-2,5-di(t-butyl peroxy)hexyne-3 were used as a crosslinkingaid and a peroxide, respectively, and was evaluated. As a result, goodresults were exhibited except that the wiring peeling strength in theevaluation of the adhesion property to the wiring was lowered to 0.8kg/cm².

Example 10

[0289] <Formation of Dry Film>

[0290] The uniform solution obtained in Preparation Example 1 wasfiltered through a precision filter made of PTFE having a pore size of0.22 μm to obtain a curable polymer composition. The solution thusobtained was coated on a glass substrate 18 μm in thickness in the formof a rectangle of 50 mm×80 mm by means of a spinner, and then prebakedat 80° C. for 90 seconds to remove the solvent, thereby forming a dryfilm having a film thickness of 40 μm.

[0291] <Formation of Build-Up Multi-Layer Laminate>

[0292] (A) After a glass-epoxy multi-layer wiring substrate 600 μmthick, which is a base material, was sandwiched between 2 dry filmsobtained in the above-described manner to press-bond the dry films underreduced pressure to the substrate by means of a vacuum laminator, theywere heated, melted and bonded by a hot press, thereby producing alaminate. The heating was conducted for 2 minutes at a temperaturehigher by 20° C. than the glass transition temperature of the copolymer.

[0293] (B) After mask films for formation of via holes were press-bondedunder reduced pressure to both sides of the laminate obtained above, thelaminate was exposed to ultraviolet light having light intensity of 300mJ/cm² at 365 nm using a UV irradiation device to completely cure theresin at the exposed portion. Thereafter, development was conducted witha mixed solution of toluene/cyclohexane to dissolve and remove theuncured portion of the resin, thereby forming interlayer-connecting viaholes. After a proper surface-roughening treatment was conducted on thesurfaces of the dry films in which the via holes had been formed,plating resist films were applied to the surfaces to form chemicalcopper plating layers in order of electroless plating andelectroplating. The resist films were then separated to form metalwiring patterns.

[0294] (C) Additional dry films were laminated on both sides of the dryfilm-attached laminate, on which the metal wiring patterns had beenformed, in the same manner as in the step (A), and the curing of theresin, formation of the via holes and formation of the metal wiringpatterns were conducted in the same manner as in the step (B). Theprocess of (C) was repeated three times in total to form a build-upmultilayer laminate having 4 layers on each side. The dielectricproperties and water absorptivity of the thus-obtained laminate weredetermined. As a result, good values were obtained as demonstrated by adielectric constant of 2.5 and a dielectric loss tangent of 0.0007 withrespect to the dielectric properties, and a water absorptivity of 0.05%.In the evaluation as to moisture resistance as well, excellentreliability was demonstrated by a percent defective of at most 3%.

Example 11

[0295] A build-up multi-layer laminate was formed in the same manner asin Example 10 except that the uniform solution obtained in PreparationExample 2 was used, and was evaluated. As a result, excellent evaluationresults were obtained as demonstrated by a dielectric constant of 2.5, adielectric loss tangent of 0.0007, a water absorptivity of 0.05% and apercent defective of at most 3% in the evaluation as to moistureresistance.

Example 12

[0296] A build-up multi-layer laminate was formed in the same manner asin Example 10 except that the uniform solution obtained in PreparationExample 3 was used, and was evaluated. As a result, excellent evaluationresults were obtained as demonstrated by a dielectric constant of 2.6, adielectric loss tangent of 0.0008, a water absorptivity of 0.06% and apercent defective of at most 5% in the evaluation as to moistureresistance.

Example 13

[0297] <Formation of Dry Film>

[0298] The uniform solution obtained in Preparation Example 2 wasfiltered through a precision filter made of PTFE having a pore size of0.22 μm to obtain a curable polymer composition. The solution thusobtained was coated on a glass substrate 18 μm in thickness in the formof a rectangle of 50 mm×80 mm by means of a spinner, and then prebakedat 80° C. for 90 seconds to remove the solvent, thereby forming a dryfilm having a film-thickness of 40 μm.

[0299] <Formation of Build-Up Multi-Layer Laminate>

[0300] (A) After a glass-epoxy multi-layer wiring substrate 600 μmthick, which is a base material, was sandwiched between 2 dry filmsobtained in the above-described manner to press-bond the dry films underreduced pressure to the substrate by means of a vacuum laminator, theywere heated, melted and bonded by a hot press, thereby producing alaminate. The heating was conducted for 2 minutes at a temperaturehigher by 50° C. than the glass transition temperature of the copolymer.

[0301] (B) The laminate obtained above was heated at 200° C. for 4 hoursunder nitrogen in an oven to completely cure the dry film layers.Thereafter, interlayer-connecting via holes were formed by means of acarbon dioxide laser scanning apparatus. After a propersurface-roughening treatment was then conducted on the surfaces of thedry films in which the via holes had been formed, plating resist filmswere applied to the surfaces to form chemical copper plating layers inorder of electroless plating and electroplating. The resist films werethen separated to form metal wiring patterns.

[0302] (C) Additional dry films were laminated on both sides of the dryfilm-attached laminate, on which the metal wiring patterns had beenformed, in the same manner as in the step (A), and the curing of theresin, formation of the via holes and formation of the metal wiringpatterns were conducted in the same manner as in the step (B). Theprocess of (C) was repeated three times in total to form a build-upmultilayer laminate having 4 layers on each side. The dielectricproperties and water absorptivity of the thus-obtained laminate weredetermined. As a result, excellent evaluation results were obtained asdemonstrated by a dielectric constant of 2.5, a dielectric loss tangentof 0.0007, a water absorptivity of 0.05% and a percent defective of atmost 3% in the evaluation as to moisture resistance.

Example 14

[0303] A build-up multi-layer laminate was formed in the same manner asin Example 11 except that the uniform solution obtained in PreparationExample 5 was used, and was evaluated. As a result, excellent evaluationresults were obtained as demonstrated by a dielectric constant of 2.6, adielectric loss tangent of 0.0008, a water absorptivity of 0.06% and apercent defective of at most 5% in the evaluation as to moistureresistance.

Example 15

[0304] A build-up multi-layer laminate was formed in the same manner asin Example 11 except that the uniform solution obtained in PreparationExample 6 was used, and was evaluated. As a result, excellent evaluationresults were obtained as demonstrated by a dielectric constant of 2.8, adielectric loss tangent of 0.0012, a water absorptivity of 0.08% and apercent defective of at most 8% in the evaluation as to moistureresistance.

Example 16

[0305] A build-up multi-layer laminate was formed in the same manner asin Example 10 except that the uniform solution obtained in PreparationExample 7 was used, and was evaluated. As a result, excellent evaluationresults were obtained as demonstrated by a dielectric constant of 2.7, adielectric loss tangent of 0.0010, a water absorptivity of 0.07% and apercent defective of at most 7% in the evaluation as to moistureresistance.

Example 17

[0306] A build-up multi-layer laminate was formed in the same manner asin Example 10 except that the uniform solution obtained in PreparationExample 8 was used, and was evaluated. As a result, excellent evaluationresults were obtained as demonstrated by a dielectric constant of 2.5, adielectric loss tangent of 0.0007, a water absorptivity of 0.05% and apercent defective of at most 6% in the evaluation as to moistureresistance.

Comparative Example 4 (Production Example of Build-Up Multi-LayerLaminate of Photosensitive Epoxy Resin)

[0307] (A) A laminate with a layer laminated on each side of a substratewas formed in the same manner as in Example 10 except that dry films(alkali development type; film thickness: 50 μm) of the conventionallyknown photosensitive epoxy resin were used, and the heating and pressbonding were conducted at 160° C. for 2 minutes.

[0308] <Formation of Build-Up Multi-Layer Laminate>

[0309] (B) After mask films for formation of via holes were press-bondedunder reduced pressure to both sides of the laminate obtained above, thelaminate was exposed to ultraviolet light having light intensity of 300mJ/cm² at 365 nm using a UV irradiation device to completely cure theresin at the exposed portion. Thereafter, development was conducted witha methyl isobutyl ketone solution to dissolve and remove the uncuredportion of the resin, thereby forming interlayer-connecting via holes.After a proper surface-roughening treatment was conducted on thesurfaces of the dry films in which the via holes had been formed,plating resist films were applied to the surfaces to form chemicalcopper plating layers in order of electroless plating andelectroplating. The resist films were then separated to form metalwiring patterns.

[0310] (C) Additional dry films were laminated on both sides of the dryfilm-attached laminate, on which the metal wiring patterns had beenformed, in the same manner as in the step (A), and the curing of theresin, formation of the via holes and formation of the metal wiringpatterns were conducted in the same manner as in the step (B). Theprocess of (C) was repeated three times in total to form a build-upmultilayer laminate having 4 layers on each side. The viscositycharacteristics (flowability) of the dry films upon the heating andpress bonding were deteriorated by the influence that curing proceededbefore the laminating since the shelf stability of the dry films waspoor, so that the adhesion properties between the film and the substrateand between the films were lowered. The dielectric properties and waterabsorptivity of the thus-obtained laminate were determined. As a result,with respect to the dielectric properties, the dielectric constant was4.1 and the dielectric loss tangent was 0.12, while the waterabsorptivity was 0.4%. As the result that the evaluation as to moistureresistance was conducted, it was found that the percent defective wasincreased to 13% due to migration resulting from the fact thatinterlayer moisture absorption was accelerated because the adhesionproperty between the films was lowered for the above-described reasons.[Comparative Example 5]

(Production Example of Build-Up Multi-Layer Laminate ofNon-Photosensitive Epoxy Resin)

[0311] (A) A laminate with a layer laminated on each side of a substratewas formed in the same manner as in Example 13 except that dry films(thermosetting type; film thickness: 50 μm) of the conventionally knownnon-photosensitive epoxy resin were used, and the heating and pressbonding were conducted at 160° C. for 2 minutes.

[0312] <Formation of Build-Up Multi-Layer Laminate>

[0313] (B) The laminate obtained above was heated at 180° C. for 3 hoursunder nitrogen in an oven to completely cure the dry film layers.Thereafter, interlayer-connecting via holes were formed by means of acarbon dioxide laser scanning apparatus. After a propersurface-roughening treatment was then conducted on the surfaces of thedry films in which the via holes had been formed, plating resist filmswere applied to the surfaces to form chemical copper plating layers inorder of electroless plating and electroplating. The resist films werethen separated to form metal wiring patterns.

[0314] (C) Additional dry films were laminated on both sides of the dryfilm-attached laminate, on which the metal wiring patterns had beenformed, in the same manner as in the step (A), and the curing of theresin, formation of the via holes and formation of the metal wiringpatterns were conducted in the same manner as in the step (B). Theprocess of (C) was repeated three times in total to form a build-upmultilayer laminate having 4 layers on each side. The viscositycharacteristics (flowability) of the dry films upon the heating andpress bonding were deteriorated by the influence that curing proceededbefore the laminating since the shelf stability of the dry films waspoor like Comparative Example 4, so that the adhesion properties betweenthe film and the substrate and between the films were lowered. Thedielectric properties and water absorptivity of the thus-obtainedlaminate were determined. As a result, with respect to the dielectricproperties, the dielectric constant was 3.8 and the dielectric losstangent was 0.09, while the water absorptivity was 0.4%. As the resultthat the evaluation as to moisture resistance was conducted, it wasfound that the percent defective was increased to 12% due to migrationresulting from the fact that interlayer moisture absorption wasaccelerated because the adhesion property between the films was loweredfor the above-described reasons.

Example 18

[0315] <Formation of Resin-Attached Metal Foil>

[0316] The uniform solution obtained in Preparation Example 1 wasfiltered through a precision filter made of PTFE having a pore size of0.22 μm to obtain a curable polymer composition. The solution thusobtained was coated on a roughened surface of a rolled copper foil 18 μmin thickness in the form of a rectangle of 50 mm×80 mm by means of aspinner, and then prebaked at 80° C. for 90 seconds to form a coatingfilm (insulating layer) having a film thickness of 0.40 μm.

[0317] <Formation of Build-Up Multi-Layer Laminate>

[0318] A glass-epoxy multi-layer wiring substrate 600 μm thick, which isa base material, was sandwiched (with the resin side of theresin-attached metal foil turned inside) between 2 cycloolefinresin-attached metal foils obtained in the above-described manner tobond the metal foils by heating them under pressure of 50 kg/cm² at atemperature higher by 50° C. than the glass transition temperature (Tg)of the modified polymer for 1 to 5 minutes in a nitrogen atmosphere bymeans of a hot press, thereby producing a laminate. Parts of the copperfoils were etched using masks to form spots for formation of via holes,followed by formation of via holes 50 μm in diameter by means of acarbon dioxide laser. Thereafter, the laminate was heated at 200° C. for4 hours under nitrogen in an oven to completely cure the resin films.Etching resists for formation of wiring pattern were then applied to thecopper foils, and the thus-treated substrate was immersed in an aqueoussolution of ammonium persulfate to etch copper. Further, resin smearremaining at the bottom of each via hole was removed (desmearingtreatment) with a permanganate solution. After the resists wereseparated, wall surfaces of the via holes and copper wiring layers wereplated with copper to conduct interlayer connection. The thus-obtainedbuild-up laminate was further sandwiched between 2 resin-attached metalfoil. Thereafter, the above-described process was repeated to obtain abuild-up multi-layer laminate having 3 layers on each side, i.e., 6layers in total on both sides. The dielectric properties and waterabsorptivity of the thus-obtained laminate were determined. As a result,good values were obtained as demonstrated by a dielectric constant of2.5 and a dielectric loss tangent of 0.0007 with respect to thedielectric properties, and a water absorptivity of 0.05%. In theevaluation as to moisture resistance as well, excellent reliability wasdemonstrated by a percent defective of at most 3%.

Example 19

[0319] A build-up multi-layer laminate was formed in the same manner asin Example 18 except that the uniform solution obtained in PreparationExample 2 was used, and was evaluated. As a result, excellent evaluationresults were obtained like Example 18 as demonstrated by a dielectricconstant of 2.5, a dielectric loss tangent of 0.0007, a waterabsorptivity of 0.05% and a percent defective of at most 3% in theevaluation as to moisture resistance.

Example 20

[0320] A build-up multi-layer laminate was formed in the same manner asin Example 18 except that the uniform solution obtained in PreparationExample 3 was used, and was evaluated. As a result, excellent evaluationresults were obtained as demonstrated by a dielectric constant of 2.6, adielectric loss tangent of 0.0008, a water absorptivity of 0.06% and apercent defective of at most 5% in the evaluation as to moistureresistance.

Example 21

[0321] A build-up multi-layer laminate was formed in the same manner asin Example 18 except that the uniform solution obtained in PreparationExample 4 was used, and was evaluated. As a result, excellent evaluationresults were obtained as demonstrated by a dielectric constant of 2.5, adielectric loss tangent of 0.0007, a water absorptivity of 0.05% and apercent defective of at most 3% in the evaluation as to moistureresistance.

Example 22

[0322] A build-up multi-layer laminate was formed in the same manner asin Example 18 except that the uniform solution obtained in PreparationExample 5 was used, and was evaluated. As a result, excellent evaluationresults were obtained as demonstrated by a dielectric constant of 2.6, adielectric loss tangent of 0.0008, a water absorptivity of 0.06% and apercent defective of at most 5% in the evaluation as to moistureresistance.

Example 23

[0323] A build-up multi-layer laminate was formed in the same manner asin Example 18 except that the uniform solution obtained in PreparationExample 6 was used, and was evaluated. As a result, excellent evaluationresults were obtained as demonstrated by a dielectric constant of 2.8, adielectric loss tangent of 0.0012, a water absorptivity of 0.08% and apercent defective of at most 8% in the evaluation as to moistureresistance.

Example 24

[0324] A build-up multi-layer laminate was formed in the same manner asin Example 18 except that the uniform solution obtained in PreparationExample 7 was used, and was evaluated. As a result, excellent evaluationresults were obtained as demonstrated by a dielectric constant of 2.7, adielectric loss tangent of 0.0010, a water absorptivity of 0.07% and apercent defective of at most 7% in the evaluation as to moistureresistance.

Example 25

[0325] A build-up multi-layer laminate was formed in the same manner asin Example 18 except that the uniform solution obtained in PreparationExample 8 was used, and was evaluated. As a result, excellent evaluationresults were obtained as demonstrated by a dielectric constant of 2.5, adielectric loss tangent of 0.0007, a water absorptivity of 0.05% and apercent defective of at most 6% in the evaluation as to moistureresistance.

Preparation Example 10 (Synthesis of Maleic Anhydride-Modified PPE)

[0326] After 100 parts of poly(2,6-dimethyl-1,4-phenylene ether), 1.5parts of maleic anhydride and 1.0 part of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane (Perhexa 25B, product of Nippon Oil & Fats Co., Ltd.) weredry blended at room temperature, the blend was extruded from atwin-screw extruder under conditions of a cylinder temperature of 300°C. and a screw speed of 230 rpm to obtain maleic anhydride-modifiedpoly(phenylene ether) (PPE). When 15 parts of the thus-obtained PPE, 9parts of triallyl cyanurate as a curing aid and 1.2 parts of2,5-dimethyl-2,5-di(t-butyl peroxy)hexyne-3 were dissolved in 45 partsof hot toluene, a uniform solution was provided without forming anyprecipitate.

Comparative Example 6 (Preparation of Thermosetting PPE Resin-AttachedMetal Foil)

[0327] A resin-attached metal foil and a build-up multi-layer laminatewere prepared in exactly the same manner as in Example 18 except thatthe PPE resin composition obtained in Preparation Example 10, andevaluated. As a result, the roughened wall surface of each via hole wasslightly dissolved by the chemical treatments upon the formation ofwiring and desmearing treatment, so that the adhesion property to theplating layer was deteriorated, and the reliability on the moistureresistance test was greatly lowered due to migration. Therefore, thepercent defective was increased to at least 20%.

[0328] From the above-described Examples 18 to 25 and ComparativeExample 6, it was confirmed that the build-up multi-layer laminatesproduced with the resin-attached metal foils making use of thecycloolefin resin composition exhibit excellent dielectric properties,low water absorption property and reliability.

INDUSTRIAL APPLICABILITY

[0329] According to the present invention, there are provide interlayerinsulating materials for high-density assembly boards, which areparticularly suitable for use in bare chip mounting of LSI chips and arecapable of forming minute via holes. According to the present invention,there are also provided high-density assembly boards making use of suchan interlayer insulating material having excellent properties. Theinsulating materials and high-density assembly boards according to thepresent invention are excellent in electrical properties such asdielectric constant and dielectric loss tangent, moisture resistance anddurability, and are also excellent in adhesion properties to metallayers and substrates. The interlayer insulating materials according tothe present invention are useful in a wide variety of fields, inparticular, as assembly circuit boards and the like, of which highdensity and high reliability are required, in fields of electric andelectronic apparatus.

[0330] According to the present invention, there are also provided dryfilms excellent in shelf stability, adhesion properties and reliability,which are particularly suitable for use in interlayer insulating filmsfor high-density assembly boards. According to the present invention,there are further provided build-up multi-layer laminates making use ofsuch dry films and a production process thereof. The dry films accordingto the present invention are excellent in electrical properties such asdielectric constant and dielectric loss tangent, and moisture resistanceand are useful in a wide variety of fields, in particular, as interlayerinsulating materials for assembly boards, and the like, of whichspeeding up and high reliability are required, in fields of electric andelectronic apparatus.

[0331] According to the present invention, there are further providedresin-attached metal foils excellent in adhesion properties andreliability, which are particularly suitable for use in interlayerinsulating films for high-density assembly boards. According to thepresent invention, there are provided build-up multi-layer laminatesmaking use of such resin-attached metal foils, and a production processthereof. The resin-attached metal foils according to the presentinvention are excellent in electrical properties such as dielectricconstant and dielectric loss tangent, and moisture resistance and areuseful in a wide variety of fields, in particular, as interlayerinsulating materials for assembly boards, and the like, of whichspeeding up and high reliability are required, in fields of electric andelectronic apparatus.

1. An interlayer insulating material for a high-density assembly boardhaving interlayer-connecting via holes at most 200 μm in diameter,comprising a cycloolefin polymer containing at least 50 mol % of arepeating unit derived from a cycloolefin monomer.
 2. The interlayerinsulating material according to claim 1, wherein the cycloolefinpolymer has a glass transition temperature of at least 100° C. asmeasured by a differential scanning calorimeter and a number averagemolecular weight within a range of 1,000 to 1,000,000 as measured by gelpermeation chromatography.
 3. The interlayer insulating materialaccording to claim 1, wherein the cycloolefin polymer has a polar group.4. The interlayer insulating material according to claim 1, which is acurable resin composition comprising a hardener together with thecycloolefin polymer.
 5. The interlayer insulating material according toclaim 1, wherein the cycloolefin polymer has a repeating units derivedfrom an alicyclic monomer having a norbornene ring as the repeating unitderived from the cycloolefin monomer.
 6. The interlayer insulatingmaterial according to claim 5, wherein the cycloolefin polymer is atleast one thermoplastic norbornene resin selected from the groupconsisting of (1) an addition polymer of an alicyclic monomer having anorbornene ring, (2) an addition copolymer of an alicyclic monomerhaving a norbornene ring and an unsaturated monomer copolymerizabletherewith, (3) a ring-opening polymer of an alicyclic monomer having anorbornene ring and (4) hydrogenated products thereof.
 7. The interlayerinsulating material according to claim 1, wherein the cycloolefinpolymer has a repeating units derived from a monocyclic cycloolefinmonomer as the repeating unit derived from the cycloolefin monomer. 8.The interlayer insulating material according to claim 1, wherein thecycloolefin polymer has a repeating units derived from a cyclicconjugated diene monomer as the repeating unit derived from thecycloolefin monomer.
 9. The interlayer insulating material according toclaim 8, wherein the cycloolefin polymer is at least one selected fromthe group consisting of an addition polymer of a cyclic conjugated dienemonomer and hydrogenated products thereof.
 10. The interlayer insulatingmaterial according to claim 3, wherein the cycloolefin polymer is amodified polymer obtained by graft-reacting a polar group-containingunsaturated compound with an unmodified cycloolefin polymer.
 11. Theinterlayer insulating material according to claim 4, wherein thehardener is selected from the group consisting of (1) an organicperoxides, (2) a hardener capable of exhibiting its effect by heat and(3) a hardener capable of exhibiting its effect by light.
 12. Theinterlayer insulating material according to claim 4, wherein the curableresin composition comprises the hardener in a proportion of 0.1 to 30parts by weight per 100 parts by weight of the cycloolefin polymer. 13.The interlayer insulating material according to any one of claims 1 to12, which is a varnish further comprising an organic solvent.
 14. Ahigh-density assembly board having interlayer-connecting via holes atmost 200 μm in diameter, wherein an interlayer insulating film of theboard comprises a cycloolefin polymer containing at least 50 mol % of arepeating unit derived from a cycloolefin monomer.
 15. A semiconductorpackage making use of the high-density assembly board according to claim14.
 16. A dry film formed from a curable resin composition comprising apolymer having a number average molecular weight within a range of 1,000to 1,000,000 as measured by gel permeation chromatography, and ahardener.
 17. The dry film according to claim 16, wherein thecycloolefin polymer contains at least 50 mol % of a repeating unitderived from a cycloolefin monomer and has a glass transitiontemperature of at least 100° C. as measured by a differential scanningcalorimeter.
 18. The dry film according to claim 16, wherein thecycloolefin polymer has a polar group.
 19. The dry film according toclaim 16, wherein the curable resin composition is a varnish furthercomprising an organic solvent.
 20. A process for producing a dry film,the process comprising the steps of applying a curable resin compositioncomprising a cycloolefin polymer having a number average molecularweight within a range of 1,000 to 1,000,000 as measured by gelpermeation chromatography, a hardener and a solvent to a substrate andremoving the organic solvent under conditions that a curing reaction ofthe curable resin composition is not caused to completely proceed.
 21. Alaminate comprising an insulating layer formed with a dry film formedfrom a curable resin composition comprising a polymer having a numberaverage molecular weight within a range of 1,000 to 1,000,000 asmeasured by gel permeation chromatography, and a hardener, and aconductive layer formed on the surface of the insulating layer.
 22. Amulti-layer laminate further comprising each at least one insulatinglayer formed with the dry film and conductive layer on the conductivelayer-forming surface of the laminate according to claim 21, wherein theconductive layers are connected to each other by forminginterlayer-connecting via holes in the insulating layer provided betweenthem.
 23. A process for producing a multi-layer laminate, whichcomprises a step (A) of laminating a dry film formed from a curableresin composition comprising a polymer having a number average molecularweight within a range of 1,000 to 1,000,000 as measured by gelpermeation chromatography, and a hardener on at least one side of asubstrate, conducting the curing of the dry film and the formation ofinterlayer-connecting via holes, and then forming a conductive layer onthe surface of the dry film and wall surfaces of the via holes toproduce a laminate, and a step (B) of laminating an additional dry filmon the conductive layer-forming surface of the laminate to conduct thecuring of the dry film, formation of interlayer-connecting via holes andformation of a conductive layer in the same manner as in the step (A),wherein the step (B) is repeated at least once.
 24. A resin-attachedmetal foil obtained by forming a film of a cycloolefin polymer on oneside of a metal foil.
 25. The resin-attached metal foil according toclaim 24, wherein the cycloolefin polymer contains at least 50 mol % ofa repeating unit derived from a cycloolefin monomer, and has a glasstransition temperature of at least 100° C. as measured by a differentialscanning calorimeter and a number average molecular weight within arange of 1,000 to 1,000,000 as measured by gel permeationchromatography.
 26. The resin-attached metal foil according to claim 24,wherein the cycloolefin polymer has a polar group.
 27. Theresin-attached metal foil according to claim 24, wherein the cycloolefinpolymer is a curable resin composition comprising a hardener.
 28. Alaminate obtained by laminating a resin-attached metal foil obtained byforming a film of a cycloolefin polymer on one side of a metal foil onat least one side of a substrate with the side of the resin film turnedinside.
 29. A process for producing a build-up multi-layer laminate, theprocess comprising a step (A) of forming a wiring pattern on the metalfoil side of the laminate according to claim 28 and a step (B) oflaminating the resin-attached metal foil on the wiring pattern with theside of the resin film turned inside and then forming a wiring patternin the same manner as in the step (A), wherein the step (B) is repeatedat least once.
 30. A build-up multi-layer laminate produced by theprocess according to claim 29.